Offlane Pusher Sniper

Overview

I've never liked Sniper as a hero much, both due to his status as a pub hero and the fact that he's generally both a weak mid and a boring safelane farmer, not to mention being a KS machine. Lately, however, I've been theorycrafting an offlane Sniper- whether with a support or solo- and I've realized that rather than AFK farming he's well suited to the role of an evasive pusher, so long as he doesn't have the burden of being in the 1 position (though even with a push build he certainly transfers to the lategame very, very well). Anyways, this guide is primarily for my own reference, and any comments/feedback/criticism is quite welcome! (Also, as my first guide, any formatting tips would be greatly appreciated).

Skills

Shrapnel:

This is one of the two reasons Sniper makes such a good pusher. While you can't level this skill much early game, as you need a couple levels in your W and E just to CS safely, the damage over time it deals to structures is absolutely massive- comparable to Pugna's Q (only a couple damage less at level 4), and at over three times the range, it's both much safer and quicker than rightclicking the tower yourself, until you get a bit more farm at least. Beyond that, it also gives a small circle of vision- normally insignificant, but very helpful for taking down tier one towers. It shreds through creep waves, and it also gives you a much needed slow; just remember that it takes about a second for it to actually start doing damage/slowing, so cast it where your enemies are going to be, not where they are. Also remember that Sniper has a very low turn rate, so sometimes it's better to just run!

Headshot:

The skill that makes Sniper, Sniper... though also one of the least important abilities in this particular build. One of the most significant problems I had in creating this build was where to take Headshot & Take Aim at levels 1-4; it's something of a Catch-22, as you need Take Aim to CS safely, but you need Headshot to actually get the last hit. Ultimately I went with Headshot level 1, as you're not going to be leaving tower much anyways, so when the creeps are under your tower at least it'll make CSing a bit easier. Secondly, the most efficient level of headshot is level two (jumping from 15 to 40 damage), so it's almost always worth taking by level three. Still, skill builds are always mutable, so if you feel you really need the extra range and are confident with your CS, go for level 1/3 Take Aim, and 2/4 Headshot.

Take Aim:

This is the skill that lets you offlane so well, and why you're able to push. With one level in this skill you outrange every hero but Lina, and with two you even outrange aghs Enchantress... and, most pertinently, towers. Use your Q to get vision on the tower if you don't have it, and rightclick away! Additional levels of Take Aim take priority, as it lets you attack towers at an even greater distance, as well as being able to do fun things like attacking towers from behind trees and whatnot- get creative with it.

Assassinate:

One of Sniper's strongest skills, and one of his most poorly used skills. So many trenchies use this ability just to finish off weakened enemies, but just look at that cooldown: 20/15/10. The only thing stopping you from spamming the hell out of this ability is its high mana cost! While the damage is great for finishing off enemies, the range and cooldown tell a different story- don't use this after fights, use it before them! Use it to harass while in lane, use it to weaken enemies before teamfights, the sky's the limit. And that support who's approaching to halt your push? She's gonna think twice about that when you've whacked off half her HP before she even gets in range.

Items

Starting Items:

This stuff's fairly self-explanatory. Standard Salve+Tango, standard pre-Basi Ring of Protection, Slippers for the inevitable Aquila, and a gg branch because if you don't buy a gg branch you're gonna have a bg. If you're going to the offlane solo, make sure you have room for your support to give you a ward, and get that ward. Don't place it on the pull spot, put it in the enemy jungle to give view of incoming ganks. The Obs ward is imperative- if your team are ***hats and don't buy wards/just don't give you any, skip the slippers and buy them yourself. Vision is your most important thing for staying alive, and staying alive is the most important thing (see Tips & Tricks).

Early Game:

My favorite early game build is finish Basi for efficient damage (remember to turn it off while laning)>Boots for staying alive>Aquila because it's OP after the +3 Agility (remember to turn it off AGAIN while laning, and remember to turn it back on while pushing!), but you can really build it in whatever order you need. If you're up against one of your counters (see below), boots might be a necessity. Stock up on clarities if you want to spam your abilities a lot, and grab a wand if you're seeing a lot of spells cast your way- it's very efficient on Sniper with his low HP/mana pool.
Maelstrom is one of your best items to get early-mid game. It gives you good attack speed and some excellent damage (once chain lightning is factored in) for a mere 2700 gold, as well as letting you push (and farm!) that much harder. It's the item that lets you finally become more of a threat than a nuisance; however, unless you're very confident in your ability to stay alive and map awareness, buying an escape item should take priority.

Escape!:

Most of the time, you shouldn't be buying both a Shadow Blade and a Force Staff. One is enough. And in an ideal world, you could buy a Shadow Blade every game, as it contributes nicely to your rightclicks (unlike the Force Staff) as well as being a much better ganking items with that sweet, sweet damage bonus, but sometimes it's just not practical. If you already have multiple invis heroes on your team (and thus your opponents are presumably warding/carrying dust to a great degree), if you're up against a Bounty Hunter or a Slardar or a Clockwerk, if you want overall greater positioning, or if you're worried about Shadow Blade's not insignificant mana cost, a Force Staff is almost always going to be a better idea. Ultimately, while they are both vital escape items, the Force Staff is much more of a utility item, and the Shadow Blade is much more of an aggressive item.
Boots of Travel should usually be your first boots upgrade; it gives you a much greater map presence, and just as important is the absolutely massive movement speed bonus. Of course, it's also perhaps the single best split pushing item in the game.

You didn't forget about these guys, did you? Map awareness is perhaps the most important thing for staying alive, which is the most important thing. If you're going to be BoT-ing all over the map to split push, you need to have vision- even with a Shadow Blade or a Force Staff, you're extremely vulnerable to ganks, being generally slow and squishy. Your supports should be buying wards on cooldown; if they're not, tell them to, and if they still don't, suck it up and buy them yourself.

Extension:

Once you have your Aquila, your escape item, your Maelstrom and your BoTs, there's a few ways you can go here. Your first order of business should usually be to grab a casual Yasha- after BoT, it's a neat +39 movement speed, not to mention all the nice Agi and AS. After that, there's a few ways to go; Mjollnir beefs up your attack speed and Chain Lightning's power by a lot, Desolator shreds through towers, and Manta style gives some much needed stats, as well as illusions, which are always good for split pushing. Popping the manta also dispels dust and silences and whatnot, as well as being able to block or distract with good micro, so it can aid escaping. The only reason Manta isn't core is because Sniper very rarely builds stats, so your illusions are going to be pretty weak- they can't even Headshot!
Special mention goes to Helm of the Dominator: it's a nice lifesteal item, but it's main appeal is dominating creeps for push (Alpha Wolf is the best for this), as well as being able to dominate lane creeps for backdooring. I personally think Mask of Madness is a little dangerous to use, but its raw power is staggering, and I have trouble fitting it into this build; if you do use it, use it wisely.

Situational:

All item builds are fluid, and these are just a few of the extremely situational items a Sniper could build. Black King Bar if you're dealing with too many disables (though your first line of defense should be to stay out of range of them), Butterfly or Satanic to start carrying hard(er), and Necronomicon because it's the peas to Boots of Travel's macaroni. Or something like that.
Finally, a note on MKB: yes, I know Headshot procs effectively grant true strike, but just 40% of the time isn't enough. Headshot vs. a Phantom Assassin is still missing about 1/4 of its attacks; against a Butterfly, just over 1/5. Even a simple Talisman or Heaven's Halberd still comes out to an effective 15% evasion. While you might be able to ignore a Heaven's Halberd on a hero like a Wisp or something, for the most part Monkey King Bar is still well worth it. Beyond that, the minibash chance stacks with your Headshot, and it's really fun to get a ministun or more attacks than no- great against heroes with long cast times and to cancel nearly-finished TPs.

Tips & Tricks

*Rule number one, and it bears repeating: stay alive. If you're going to the offlane solo, so long as you sap xp and don't die you've done your job. Beyond that, you need all the gold you can get, and dying interrupts that sweet sweet farm. The key to playing an effective Sniper is to do things smartly and safely.

*Before level four, you should be hugging the tower most of the time- don't do anything dangerous, don't harass unless it's completely safe, and don't go in for CS unless it's completely safe, because let's face it you're probably not gonna get it. However, once you outrange everyone and have that neat +40 damage from Headshot, you can take a much more active role in your lane, which bring me to my next tip...

*Shoot first, and then shoot them some more. Early game Sniper can be an absolute nightmare to lane against, since you can pop them with your rightclicks with near impunity. Since you outrange pretty much every attack and every ability, it'll be obvious if they're about to retaliate, so just back off, and keep out of their range all the time, while keeping them in your range and attacking them whenever you get the chance.

*Never think you're invincible. This sort of falls under the "don't die" section above: until you're six-slotted with a satanic and a butterfly, you're going to be squishy support levels of squish, and as much as you might be an absolute terror, as soon as you get hit by a disable you're just as frail as anyone else. This is why positioning and map awareness is so important.

*Your biggest strength is your range, and therefore your biggest weakness is gap closers. Things like blinks, Clockwerk's Hookshot, Tusk's Snowball, and invis heroes without detection can give you a really bad time. Even worse are abilities that bring you to them- Disruptor's Glimpse does just that, and it'll easily outrange you as soon as he puts a couple levels into it. Pudge is another one, and if you have a hard counter, it's probably him.

*A note on invis heroes: another reason map awareness is so important. If there's a Nyx or Bounty Hunter missing and you're not yet farmed enough to manfight them when they get the drop on you (and you likely never will be with Nyx), you either need to place Sentries everywhere or just never leave tower.

*Avoid these *******s:

Pretty much all of them can come out of nowhere and seriously wreck your ****. That's not to say you can't win against them, but you're almost definitely going to have a bad time.