General advice / help needed.

Find yourself on DOTABUFF (or similar service), post a link, and there's plenty of people here that will be happy to take a look at some of your games and offer advice. There's tons of guides out there on general improvement, but specific advice relevant to you may be more useful...

Just by a quick look, and no means a deep analysis, but just because it might help, two notes:

1) Your item build in some heroes looks like open to improvement. Some random examples, just to illustrate what I mean: you are a support Bane, there's almost never a valid reason to get a Ring of Aquila. There are other items that fullfil those needs better, and you're not getting what you really need in the hero, including the possibility of safely using your spells ( Glimmer Cape, the new Aether Lens, Force Staff cause positioning yourself carefully is still the most important thing in a support). Second random example: Venomancer is an Agility hero that is mainly played as a support, as you did, so he has little mana to work with and very mana intensive necessities, so buying a mana expensive item like Mekansm, specially without other mana items (and a Force Staff instead of Blink Dagger, which also costs mana), is a bad idea, because you will never have enough mana to cast everything you need.

One thing common to both these examples is the fact that if you research the most common builds for these heroes, you will notice none of these items are in any of those.

So my advice is, for every hero and in every match: consider carefully the items you're gonna buy, as soon as the game begins, based on the hero you picked (if you're a support, you can't be greedy and you will have mana and positioning issues, if you're a core you will need damage and attack speed, etc.) and the enemy team composition (in the recent Shadow Fiend game, you did a Silver Edge, which was the perfect item choice against your enemy team, for instance).

Before playing a hero, take a look at guides, both in sites like this and on YouTube (guides and games from high skilled people, from coaches like Purge or even championship games). If everyone is buying specific items on a hero, and avoiding others, there's a reason for that, and the correct itemization can actually be the difference between losing and winning games.

2) Second note: You always change the heroes played, and they also vary imensily on roles. If you want to improve steadily, this is not the best way to do it. You should instead pick a role and try some heroes that fullfill it for a time, and also not just skip hero from game to game.

My advice: pick your favourite role and something like 3 to 5 heroes and spam them for a bit, after some researching.

Dont' take me wrong, I don't mean you can't get better playing such diverse heroes as you do now, you can. It just takes way longer, because you're always changing mind set and you're never getting really good with any, just scratching the surface on all. Mastering a hero requires tons of experience with it, and repetition and error.

My real example: the only hero I consider I really know how to play is Crystal Maiden. I have almost 400 games with her xD No other hero gets even close, and even if of course I also still have a lot to learn with her, I have more to learn when it comes to heroes that I played only 50 times, and even more if I played them 10, and so on. I also noticed I started playing better with her when I wrote a guide on this site, because it made me do a lot of research and for the first time really spend some time thinking on the hero and its characteristics. I also for the first time discussed other item and build options with people here, which made me learn a lot, and I watched many competitive games. So you see, there are several paths into getting better, I suggest you pick the ones you like the most and try them with some selected heroes.

Hope this helped. Good luck!

Can't see anything really bad in your builds, they look ok, you've been improving your stats steadily. It's likely a "skills" issue. Could you post up a few games you'd like someone to look at?