I m a newbie on dota too,juz learning for one month.The oni hero I know how to use is tinker.And i always buy the same item.And for now,i m used to this hero.

In the beginning,the first few days i played,i keep dying as killed by the opponent,then after few times in playing,I know the way to survive and farm.And for tinker,it is always a good hero to farm as its 3rd skill is damn useful.Although cant kill hero,but i still can gain money on killing creeps.But the money i gained,i dono where to spend as i still not too good in buying item.

Juz go for one hero that u really like and felt useful,then after use to it,it is the time for u to go for melee hero as ranged hero or int hero is too hard to play at the late game.

Good luck to both of us on learning dota,hope to get pro on this game.All the best dude!

Have fun on it.