Just go and lose. If you are godly good somewhere within a month of losing and costing your team the match you will start learning, if you are average, somewhere within the year it will happen.
Lose, learn, and develop a motherfreaking adamantium skin against what your team thinks and says. Take the good, leave the bad. And have fun, not much more you can do but that.
Also, did I mentioned you will lose and you will cost the team the match? Especially if you are not familiar with RTS controls. But we all did, so don't sweat it
Edit: If you want educative videos... well, i wouldnt reccomend them till you actually knew what you are doing in general... but if you really want i would reccomend this:
- http://www.twitch.tv/merlinidota
- http://www.twitch.tv/aui_2000
Merlini is also starting some tutorial vids, but they are not for newbies. And at any rate, watching those two and hearing what they say will make you a good player almost for sure.
Edit: Also, if you want to see the highest current level of dota, I would suggest you this VoD:
- http://www.joindota.com/en/vods/3131-g-league-semi-final-lgdcn-vs-ig-game-2
If nothing but to see how the top dogs perform.
And another Edit: I learnt a LOT of this vid, but might be a little advanced:
- http://www.youtube.com/watch?v=QXne3KrQ1Ng
Dendi (probably the most gifted DotA player) saying his toughts about solo mid, the position he plays.