You want to E pretty often, it zones the enemy adc off of the cs and makes them antsy. once you land an e follow up by placing a w down then immideitly q on them for some damage while your adc attacks, the plant is ranged so itll attack for quite some time.
In teamfights your goal is to e high priority targets such as assassins or the adc. ult after you get a good e off and place your w rapidly in your ult. q to do some damage and if it turns sour peel for your high priority allies. e chasing enemies and make sure your teammate gets out alive.