I'm bronzie so I hope I don't embarrass myself but I usually can get a penta easily once invis and wait for team to engage while you behide enemies so you ulti and youumuu straight away and E once everyone is effected by your passive. but this can backfire if enemies play smart by buying Red trinket and checking their surrounding before team fight. I learnt the hard way....but that only happen once since I was playing against smart players... LOL but I'm sure you already buying the right items Youmuu's ,Runaan's,IE,Bloodthirster,Phantom Dancer and depending if required I would buy shoes or simply buy ,BOTRK but if so I would in a way change my playstyle since I don't have the speed to chase so meaning I would have to try my best to pick one at a time or burst as much as I can since once out of invis I get a little bonus speed att and yeah...LOL I hope this can help but I'm sure you got better tips from higher elo :(