ok... as a start...
go for the following build..
1.Boots
2.Power Treads
3.Null
4.Null
(start saving for soul booster)
5. soul booster (ready by lvl 10)
6. linkens sphere (optional..its wat i normally do)
7. sell nulls and get another soul booster....
8. boots of travel..
for me,
i would max out missile and get lvl 4 of laser and at least lvl 2 of march.
use march to creep... ur ulti should be at least lvl 2...
i would normally spam my missiles by lvl 3...so at least they can suffer dmg and go back their base, while i would go and leech experience...by lvl 4 missile, things should go ur way liao.. u should be able to get a soul booster... so u can spam quite alot...u can also get a void stone.. for me, i would borrow from my techies team mate, thats why, u must psycho ur team to get a techies.

the rest of the game, just sit back and ks...

make sure u plant observers...so u can ks better