When I do a beat I usually begin with the kick-snare-hat (or cabasa or tabla some other complimentary drum sound) pattern, sometimes laying out the main kick-snare on one track and layering additional snare tracks as necessary. Often I'll add swing to my snare-only tracks until it has a bit of a semi-lag groove to it. I don't worry about the specific sounds until I've got the beat moving, at which point I'll try swapping in different kits.
Recently I've begun setting up drum kits on other samplers that load faster than the MPC (already mapped out to the MPC's pad note numbers) so that I can swap kits quickly without interrupting my workflow.
After that I layer my bass or whatever else and continue from there.
Often times drums sampled from the same break make excellent companions when played in your own pattern, as the sounds just mesh. You can feel that they were part of the same kit, instead of just random sounds thrown together. Feel free to normalize and layer so the sounds are fatter but this will many times give your drums sound like a real break rather than a programmed beat.
Another thing that adds realism to a beat is varying which particular snare sound is hitting and changing it up throughout the sequence. Try playing with velocity, especially in hihats and similar sharp sounds. If your actual velocity hits are too quiet, adjust the track they're on by turning up the Velocity %. Add those hats that cut each other out the way a closed hat would kill an open one, by setting up the closed hat pad to kill the one with the open hat.
I guess when you say "live drum sequence" you mean a real drummer.
Anyhow, that's about all the tips I've got at the moment.
Peace,
-tank.
You don't know what I know
Cuz you aint seen through my eyes
This spliff is always lit but it's a natural high
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