Don't miss your skillshots and remember to use Runic Blast. Use your nudge to get Cho out of bad situations or CC.

A lot of Gall's talents can be swapped out for different situations.

Level 4
If you are focusing on siege/laning, go for Runic Persistence instead of Bomb's Away.

Level 10
Both heroics are very viable, though I prefer to go with Twisting Nether while my Cho goes for Upheaval.

Level 13
Rising Dread is a nice damage boost for your orbs, but in most scenarios you'll get more use out of Searing Shadows.

Level 16
Every talent at this tier is great, and you should pick between them based on the enemy's team comp. If you go for Leaden Orb, you might want to grab either of the level 13 orb talents to synergize with it.

Level 20
If you chose Shadow Bolt Volley at level 10, you should grab Shadowfury instead of The Will of Gall.