When I create a Drum 'N Bass beat I start with a simple idea created in a drum pattern sequencer, split up into 4/4 at 16 hits per measure and a BPM of around 160 - 180bpm. Feel free to go lower or higher and experiment, but if it's too slow it becomes trip-hoppish or breakbeat and if it is too high it tends to sound like break core.
Place a good Kick drum sound at the first and eleventh beat in each measure. I like to use a punchy acoustic/live kick drum. Try to stay away from the technoish 909 and 808 drum sounds. Try to find some really unique ones. You can place others hits as the measures progress. Try changing between the third, seventh and ninth hit.
As for snares, pick one that will stand out and try pitching it up a tad and adding a slight reverb. I usually start with the fifth and thirteenth hits. You should also try adding a few ghost beats, that is, drums with velocity changes to add percussion to the beat. I also change it up by adding snares on different patterns generally switching between the eighth, tenth, and fifteenth hits, mostly the tenth on the fourth pattern.
Percussion can be a trick getting them to stand out yet at the same time, not drowning out anything else in the track. Try adding slight reverb and panning to keep it out of the way from the main groove.
With high-hats, create two patterns for the hats (more if needed). One should just pull the beat together; just mix in with the groove and experiment with different sets of hats and different positioning. The second high-hat should be in double time, that is, faster and driving for after the first drop.
With congas, bongos and other percussion, these should also be split into two gooves as with the high hats. One for the main beat and one for energy and drive.
Other than that, you should get a good sub-bass drum and use it to accentuate the main kick-line. Remember to not overdo it. Tone it down and keep it from interfering with the bassline.
Then you can search for choice breakbeats and slice 'em up in your favorite chopper. I recommend using the slicers in Acid or Reason. I prefer them over the fuity slicer. In Reason, I like to let the loop run, then go into the editor and add hats, snares and kicks in a neat and new style. This gives it a new appeal by changing some of the velocities of the slices.
For added fun: in Reason with the dr.rex loop player try changing the lfo on the loop player. Move the rate all the way to the left and the amount all the way to the right or at about 3 o'clock-ish. Then change the destination to filter and the wave form to the next to last. Now hit record and as the song plays you can switch the destinations from filter, to pan and oscillator. Then after you lay that funky trash down, adjust the filter levels and other knobs and isht.
To fade the beat in, start with the amp envelope attack turned all the way up and then drag it down to acquire the fade or perform the opposite to fade it out.
Hope this helps some people! If anybody has any other questions about DnB production, PM me, I am willing to spill a little more info.
For some sweet drum samples of all types that are damned good quality go to: Meanbeat. For those of you trying to create DnB in Fruity Loops Studio 4, go to FL DnB Tutorial.