I like to play this game!
I prefer AD Ranged Carrys (Vayne, Ashe, Caitlin, Graves, Corki, Urgot, etc.), because that's the highest % of win I have. For newbies? Just play and learn how to play AGAINST champs. That's usually harder than learning how to play with any champ. I haven't played blind pick much recently, so it's hard for me to give many tips :S. I guess some things to keep in mind is 18 creeps(minions) slain = 1 kill. So make sure you last hit as many creeps as you can, the whole game!
A warm up I usually will do is going to a custom game, buying boots and head to a lane. You can only hit each minion once, and no abilities. You want to aim for 140 creeps slain by 13 minutes. It will get you warmed up for last hitting, and getting that cs! (creeps slain).