well fill for example is when you go 7 times the normal beat, and then the 8th is a tad different to keep things interesting - then you start over - 7 times normal beat - maybe another fill, a little different again...
If you use FX with breaks/beats, stay clear of these (they are stereo field effects): Flanger, Chorus, Delay, Echo. Reverb can do in small decay times (ie. how long it plays, go for under 50 milliseconds) and keep the dry/wet mix (dry = original sound, wet = reverberated sound) close to 100% dry. It can bring life to dull drum mixes. Although these beats of yours sounded fine apart from the stereo thing.
Open up the samples you use for drums in a wave editor (soundforge, cooledit, anything) and there you can convert to mono. in soundforge it's the process menu if i remember right and then channel converter -> stereo to mono.
phew!