How to program a drum fill
Typically, drum fills are programmed with a drum instrument using MIDI information to sequence the pattern. Alternatively, they can be created by chopping up audio drum loops, using bespoke drum fill samples, or sequencing one-shots.
How to build drum fills
The first thing to do when building a drum fill is to decide where it will occur in the song. This will typically be at the end of a section. Secondly, the basic rhythmic idea needs to be defined, and this can be anything from a light variation on this existing drum pattern to something much more dramatic, though typically a live drummer would try to keep the groove of a track flowing through a drum fill. Thirdly, this idea can be fleshed out with extra drum sounds and subtle programming touches.
How to program real sounding drums
When your goal is realistic-sounding drums, it’s important to use drum sounds that are authentic and suited to the style of music you are creating. Also, if you’re after a natural sound, it helps to think about how a real-life drummer would play, and program the part accordingly.
How to make drum fills sound better
Steps you can take to ensure your drum fills sound their best include making sure that you’re in-keeping with your track’s groove and swing, using appropriate velocity modulation where necessary to get a naturalistic feel, and mixing them in a manner that fits in with the overall project.