i dont use FL but i kno you draw in the drum pattens. (inless its changed)
Make sure every sample is clean sounding and the sample starts at every transient. (this will make it tight)
use multiple kicks and snares to give it some beef.
ie a heavy sounding kick and punchier sounding kick.
same with snares etc etc.
layer with some breaks, high pass some, low pass some.
keep building until you like it.
use shakers to give it some shuffle,
using ghosts notes (quieter hits) in between kicks and snares with also give it some groove.
hope this helps, my brain isint working this mornin so it may not make sense. hah