I've always been a ear drummer; I can read simple music if I have all night, which I generally don't. That's the luxury of not playing for a living. The songs I play are generally pretty simple anyway (they ain't exactly
Larks Tongue in Aspic) so my main memory aids are just short notes like "Colin intro two bars", "guitar solo 16 bars", "Glenn sings I can't stand the rain x 4 then out" etc. Verrry basic
... but it helps.
Apart from noting arrangements I try to work on smooth transitions, e.g. moving smoothly into a verse after a fill at the end of the middle 8. Sometimes I can get worked up when playing a "hero fill", play it like a demon, and then take the best part of a bar to settle again. The mug punters will be impressed, but it's those little things that can change a performance from being "just ok" to smokin'
I also work on the middle 8s and the support of solos at home with a metronome because they are the "danger spots" when musos get excited and want to speed up. I want to know how the beats and transitions feel when played in clean time. Again, it's not tragic if you speed up a little in the heat of battle in a band with friends, but it's a bummer if the band or producer are going to judge you.
I also like to practice the basic beats of the song and try to work out how it can sound
special, even if it's a really simple beat. I've heard anough brilliant drummers to know that even the simplest lines can sound magical if you just get it the right way - with accurate timing, dynamics that give it a real pulse and hitting the drums/hats/cymbal in a sweet spot.
Of course, as a hobbyist, my magical moments tend to be interspersed with moments of clumsiness, but it's something to shoot for