How to proceed as a new player

Watch teams that have very skilled supports (since that's what you seem to plan on doing as a general role). I would recommend teams in which the supports can be really focused upon such as Alliance (Akke and EGM are really good), DK if you want Asian teams, speed gaming maybe?

Rox.Kis is on a roll at starladder right now, if you want some underrated teams.

Overall any tier 1 team is ok.

(Vici Gaming, Speed Gaming, TongFu, DK, iG, Na'Vi, Alliance, Fnatic - I may be missing some teams.)

thx for the hints guys!

I am 7 Hero's short of completing my quest. Then its time to pick one to prepare for pubs.
Should i focus on only one hero in the beginning or is this a bad idea?

It is not as easy as saying "I will play this hero for the next 10 games" because you have to react to both your team and the opposition. So I suggest you read up on the type of roles and perhaps pick 1 hero from each (based on what you have discovered) so at least you can pick from a small pool intelligently for each game - I still do this.

Oh and BTW - a good youtube channel to watch is "RainJarGaming" - he knows his stuff, records and commentates full games and talks through the good / bad bits of his and other plays. He also records games that are "randomise engage" where he gets a random hero and a random item set he must stick too - which is great as he will talk through how the items are good / bad for the hero, which is a major part of learning the game.

I think it's better to focus on a couple Heroes - maybe 4 or 5 - and pick one depending on the situation: for example, Lion is a great support when you lack disables but Lich is better teamfight-wise and gives more safety to hard carries; Crystal Maiden is also good and you might have to pick her when your team needs mana (thanks to her passive) and you have a laning partner that can easily kill dlsabled enemies (Gyrocopter, Lifestealer, Chaos Knight...). They also have pretty much the same item build: Animal Courier, Tranquil Boots, Mekansm and, every time you can buy them, Observer Wards. You're expected to complete the Meka in ~25 minutes if costantly warding and going for Tranquils.

Same thing if you want to play carries, but the item builds and amount of farm required may vary: that's why you should focus on supporting for a few matches (at least) and have someone that can suggest you those carries that are strong with little items.

I finished my marathon yesterday evening. Played another bot-game as lion for jumping into my first game vs. players. Went ok, my Team won in the End and i endet up with 5 kills, 10 death and 18 assists as Lion support. Had a lot of fun and also very nice team mates + enemies. No flaming, laming or name calling.
I will continue playing lion for some more games because watching some videos with him gave me some new ideas and he seems to be a lot of fun and relatively easy to handle.

I watch purge (http://www.youtube.com/user/PurgeGamers) to try to see some reasoning behind item/skill choices. I dont follow what he says religiously but it helps me expand my mindset, which imo is one of the biggest thing thats needed in dota...the understanding of fluid builds and not just using the same items and skills every time.