I've felt lost lately in DOTA2 playing against heroes that I have never seen in a game before.  At the same time I was getting frustrated playing the same heroes over and over because I felt comfortable with them and ending up with completely different results.  One game I will dominate as Viper and the next one I can't even scratch my laning opponent.  To force myself to expand a bit and help learn about the numerous heroes in DOTA2 I have switched to playing Single Draft mode.  Each player is randomly given a choice of three heroes to choose from (one hero per main attribute type: intelligence, agility, or strength).

Since this change I have played games as Phantom Lancer, Nightstalker, Omniknight, and a few others I have almost never seen in pub games before.  I found myself doing well with some such as Phantom Lancer, but not feeling like I really knew why I was doing well.  That forced me to research the heroes a bit and actually learn something (like how to control illusion minions!). 

Out of all the things I've done in DOTA2, this is easily the change that has resulted in the most knowledge gained on my part.  It has also wisened me up to some intricacies of DOTA2 which I can explore more as I find heroes I enjoy playing.  My end goal is to have at least ten heroes I feel comfortable playing in a pub game, which is about where I was with League of Legends (though in LoL I felt like I could far more easily pick up new heroes).

For anyone playing DOTA2, I highly recommend some time in Single Draft mode to open your opportunities to try and learn other heroes.  Its a surprise each time you load up a game and if you care about team composition, single draft's randomness can land you some wonderful learning opportunities.

NOTE: Yes, I understand this makes some players angry as they don't want "scrubs" using Single Draft as a sort of testing bed.  However, the fact that the picks are random, there is always the chance of a team being shafted.  This makes the match all the more fun in my opinion.