Keep distance.
After lvl 13 target warrior role heroes first. Becouse of the Giant Killer talent and your splash damage in Siege Mode you have a great damage in area this way.
Keep Thrusters for escaping and use it from Siege Mode if the enemy can reach you.
If your team can protect you and makes sure you have the sight you needed, you can dominate the enemy team.
I suggest you to sit on places where you have sight everywhere near you. And not in bushes. Becouse of autoattacking helps a lot, becouse at the end of the game you cant even see the whole area of your range at one time.