So you want to carry disruptor.
AT THE FOUNTAIN: if nobody buys the courier sacrifice clarities for the courier you can buy them later if needed.
IN LANE: wait till thunderstrike is level 2 to start harrassing, use your circle to trap and right click when you can. keep the harrass going, and farm boots and urn.
IN GANKING PHASE: use your field-ulti-thunderstrike-urn combo plus rightclick to kill everybody, use your ulti often the cooldown isn't high. Count the field seconds and when it's over glimpse them back into the ulti for the finishing blows.
IN TEAMFIGHTS. you can initiate ONLY if you can trap all the enemy core heroes inside your kinetic field and ulti, if not, someone else should initiate and get focussed, so you can cast your ulti on them trapping most of the enemy team in it.

Disruptor's an awesome early to mid game ganker, although he hasn't got a lot of lategame potential you can dominate the early and midgame with your insane damage output, so don't back out on any fight and keep looking for ganks with your team. They need to believe in you.