When u see an enemy u can towerdive easily u only need to hit Siphon of Destruction than flash to him hit mace of space and use ult and ignite to pick up the kill and an enemy ghost to push the tower. when u did everything right u didnt lost much HP cuz when u hit all skills ur shiel(passive) takes all the towerdmg.

When u see the jungler come u have 2 ways.
1st way: U use all ur skills to burst the enemy champion with the lowest HP or the lowest resists.(only do that when u realy have got enaugh dmg and u know that u can get him)
2nd way: u use ur creeping death on urself and hit enemy minions with Siphon of destruction and flash/run away in ur tower (when there are no minions u only use creping death and flash/run away) this is when u know that u r not the best one in this game.

VS a melee its realy easy u only have to go to him and hit him with ur Siphon of Destruction to harris.
VS a range its not so easy a range u cant hit all the time with ur Siphon of Destruction u have to try harris him a little bit with the creeping death and when u have the chance to hit a Siphon of destruction than hit him.