This tip will make your drums sound more dynamic and natural will work in software, sampler, or korg/roland grooveboxes.
1. To make single drum samples sound more natural make a random +8 depth pitch mod. Set to random oscillation. This attempts to make multiple hits less predictable.
2. Use accents in your step sequencer.
3. Route the bass and snare to a guitar distortion pedal. Use the EQ and gain to subtley tweak the sound. This works well if your drum sample rom is too clean.
4. Layer multiple snare samples. On accents both samples are triggered; Non-accents a single, main snare sample will suffice.