Help on playing Evelynn?

I really like playing her as she's fun to play and unique, but I can never have a good game with her. Either because she's been nerfed so heavily/every other champion outclasses her, or I just need more practice.

Anyhow, just wanting to ask for tips on how to play her. I'm trying to go stocky AP with her, such as Runic Echoes into Rylai's, Hextech Gunblade, then defensive tank items that are situational, like Deadman's for armor or Visage/ROA/other items for magic resist and add a Lichbane if I can. I go with AD reds, armor yellows, half scaling MR and half flat MR blues, and AP Quints. For my masteries I go 6-18-6 (Please note I was just trying this last night. I will most likely switch to either 0-12-18 or 12-18-0).

My jungle clear is usually fine. It depends on what side I'm on. If I'm on blue, I go for krugs, if red I go for gromp. Then either blue/red to wolves/birds. At level 3 I try to gank. I try to look for fun cheese ganks to do to have more fun. For instance I read on Reddit I think it was that one person likes to hit level 2 quick then sneak into the bushes top lane behind the enemy laner and quickly smash a ton of Q's with E and hopefully get them to either flash or die for first blood (this person also likes to take ignite. I'm not to that part yet, I still need my flash).

For me, I just can't get my burst out quick enough compared to the rest of the champion pool. Her ult is so weak and such a long cooldown oh my God. Even if I hit 3 people with her ult, it's hard to get damage out to kill people.

Maybe she just doesn't do well in the meta, I don't know. Any help is appreciated, as long as it isn't rude.

Thanks!