Hi, new to MOBA, new to DOTA 2. Random or focus on one hero?

I very much agree with this, support heroes are easier to play as a beginner because they have high skill damage, usually range, and can just stay back safely while fighting/harassing other heroes, and only have to really worry about helping the team instead of leading it.

Some heroes I like and would recommend are Lich, Lion, Shadow Shaman.
I would also recommend trying Dazzle since you said that you like Witch Doctor.

I wouldn't recommend Random until you've tried most everything at least once, the risk of getting heroes like Chen/Enchantress/Invoker that you may not be prepared to use at all is something to consider.

hey guys!

i'm back. didn't notice that my post has attracted many replies. after more than a month playing, i am pretty familiar with the game now. i find myself very useful whenever i roll support, lion and shadow shaman are obviously very annoying. sometime the opposing team even focus on me rather than the team carries :)

i am now rolling towards what the team needs rather than rolling what i am familiar with. if i wanna random, i make sure i am the first one to do so. so the team can compliment the other slots :)

thank you for your replies :)