One could copy the synth over a couple of times, then change thing's like the filter type (Comb and BR/Notch always work wonders), or cent (pitch detune). Next, play your part once with one synth, then play your part again with a slightly changed copy of the first synth etc etc...
As mentioned above, make use of LFO's and envelopes tied to everything you can tie it to (filter freq, filter res, pitch, pan, volume, pulse width modulation amount, wavetable position, distortion amount, fx dry/wet amount etc)
Use automation within the sequencer to change things as and when you need the change. This works better than an lfo sometimes, as lfo's generally cycle & repeat.
Try building your drums around the bass instead of the bass around the drums, that way, you won't be so stuck in 4x4 140bpm syndrome..!! (not that you necessarily are... I'm jumping to conclusions..)
Replace part of the bass with a sound effect or synth/instrument, and layer a sub underneath (like a low sine wave). This will add interest for listeners who will automatically fill in the bass for you. (Remember Craig David Bo selecta... Boing!)
Listen to your favourite tracks, and try to figure out each seperate element in the track that you can hear. Ie Kick, snare, hihats. Shaker, weird effect 1, weird effect 2, Bass tone 1, bass tone 2, bass wobble drop, long ambient pad sound, voice sample fx - echo's, reverbs, phasers/choruses/flangers etc etc........
try making music that doesn't involve basslines! Switch it up for a bit and make a piano piece....

or something