Help! I'm Bad at Laning

I play a lot of ARAM because personally I think the faster pace makes it a bit more fun than classic, but on the occasions that I do try Summoner's Rift, I find that I'm terribly at laning!

I don't know why, or what I'm doing wrong. I've read a lot of guides online, watched a lot of videos, even spectated ranked plays often, but I don't know why I'm just so bad at laning. Every game, I would start off losing the first lane kill, or the first three. When mid game starts I usually get better, and by late game I essentially become a carry, no matter what champ I'm playing. This just really frustrates me because I'm terrible in early game, whether I'm sup or ADC or even frickin jg. So do y'all have any tips or whatnot so I can actually improve?

I am not exactly what you would call an amateur; I have over 600 wins in ARAM right now. I know how to last hit, push a lane, freeze a lane, trade, gank, roam, and set up vision. But for some reasons I just can't win my lane, no matter if I'm using a lane bully like Darius or Caitlyn or a high sustain like Akali or Sona.

Any tips would be greatly appreciated. Thank you very much!