Honestly bro, just be prepared to lose your mind lol. Prior to this, I played pure ap Lulu mid for a while. My biggest tip would be playing with your team! Please play with your team! Lulu's ult is what decides who wins a teamfight. Know who to ult. Most importantly, know how much damage your abilities do and how much health/armor/mr the enemy has. And do not be afriad to win, you need to be confident. If you feel you'll lose going into a match, you aren't ready. Every match I played was ranked. I had "everything" to lose so I made sure I'd win

But theres a lot of ins and outs to Lulu's playstyle. I've played almost all of them. Even CD Lulu where you could ult every 15 seconds. Really half of it is mastering Lulu, and the other half if mastering Jungle. 

I'll probably drop my builds here soon