There are a lot of drummers each one with his own style. As a drummer myself when I started I wanted to do a lot of fills and playing the groove with ornaments, but nowadays after taking a lot of classes, being in a band, feeling the drums, I feel that the fills are also ornaments, and playing the groove with groove and dynamics is the more important on drums. When the drummer is confident with the groove will add the appropiate ornaments as fills or small details. Check the last part if there is a lot of terminology that you don't catch.
So, my opinion is:
- Write the main part, the groove (or the grooves) as a loop
- Put certain parts with fills or ad libitum to the drummer to escape the groove, but do not force the drummer to do something complicated, it can affect the more important part, you know, the groove.
How to write a groove
There are certain rules, that can be followed or not. The drummer plays the hihat or the ride cymbal in 1/8 notes and the snare in two and four, asuming a 4/4. Then add the kick drum in parts where the bass guitar would play. Something like that:
1 2 3 4
How to add a fill
Fills can be 1, 2, 3 or 4 beats long. It depends on the habilities of the drummer, but every drummer can play 1/16 notes alternating hands. Add rests, kick drum, accents an orchestrate this around the kit to make a fill. The following fill is 4 beats long.
1 2 3 4
Use the fills with wisdom.
Groove: It has two meanings, it is the main part of the song, that repeats itself, the rhythm. Playing with groove is also playing with a feeling and a style that makes the song shine, this last meaning can't be written in a musical score.
Fill: It is a part that break the main loop, to go to another loop or to go back to the main. They add tension, that will be released when coming back to the rhythm.
Dynamics: Playing the drum with accents, ghost notes or slighty before or after the beat, giving the song a certain character.
Ghost notes: Unaccented notes
Orchestrate: Playing some pattern on different drums or cymbals, taking the role of the orquestra leader, while the orchestra is the drum kit.
If you don't know ascii drum tabs there a guide to reading them.