My phone has never lagged once. I think you are under some major placebo here, or just don't have any idea what you are talking about. I had a Samsung transform that would lag on screen off/on, and would frequently hang for over five minutes upon loading any app, even though I only had 6 apps total.
But either way, here are some tips on fixing your "lag"
Laggy app loading = rngb seeder app set to aggressive
Laggy transitions / graphics = force gpu rendering
Laggy scrolling / polling = V6_SuperCharger by zeppelinrox (RUN THE SQLITE OPTIMIZE)
Slow boot up = convert from init.d to userinit.d
Not quite as snappy as you want = cpu Tweaks
Still slow = interactive kernel Tweaks, remove vsync, 16bit shaders, purgeable assets
Now finally, make your userinit clean up on each boot, by zipaligning, sqlite3 db vacuuming, cache clearing, and have the last script kill it all.
Also, I can send some simple apps that do a little cleaning when the screen closes if you'd like.
Sent from my DROID RAZR HD using Tapatalk 2