TMe -First of all, you'd be wise to spend even just one hour with a professional instructor. Technique is #1 if you want to develop any stroke to the fullness of your potential.
Off the record -what worked in making my doubles what they are (although I'll never stop trying to improve them further) was taking it a step further....I spent months practicing triplets....LLL RRR LLL RRR. This is a simple answer and again technique has to be #1, but doing this REALLY helped to make my double strokes burn.
The advantage, I believe, was that the triplets help to force a drummer to control each stroke. With doubles, I've seen many drummers letting the second stroke merely bounce from the first. This leads to a sloppy sounding roll. That's not to say that it's NOT a bounce....it IS. But it's a controlled bounce! The second stroke is aided by your fingers, while the primary first stroke has a little more involvement with the wrist (and fingers).
Check your doubles on a floor tom -you should be able to maintain an even stroke on this larger, looser surface. If you were merely depending on a bounce, you'll notice that on this surface (floor tom) that your double stroke becomes uneven and sloppier than on a tightly tuned snare drum or pad.
Although I didn't practice this particular exercise much -I have a friend, a great drummer from Toronto, who swore by it. To overcome the tendency to have a weak second stroke, he often practiced accenting that note (capitol letters as accents): rR lL rR lL
Take it a step even past the triplets and practice 'Stone Killers.' You can find them in Joe Morello's book, 'Master Studies' and elsewhere.
To get a great double stroke, you'll need to go past merely practicing doubles. Use a metronome and record your progress. Remember the key is to always relax!
Mix your routine by playing bars of mixed rudiments: singles; doubles; paradiddles (paradiddles incorporate a double in each); triplets; quads, etc......
RLRL RLRL RLRL RLRL RRLL RRLL RRLL RRLL
RLRR LRLL RLRR LRLL LLRR LLRR LLRR LLRR
RLLR LRRL RLLR LRRL RRLL RRLL LLRR LLRR
LLLL RRRR LLLL RRRR LLRR LLRR LLRR LLRR
LLLR RRRL LLLR RRRL RRLL RRLL RRLL RRLL
RRR LLL RRR LLL LLL RRR LLL RRR
RLR LLL RLR LLL LRL RRR LRL RRR
and on, and on, and on.....
Once your doubles are really starting to happen for you, make sure to run through your routines with accents. Ex;
RRLL RRLL rRlL rRlL
RRLL RRLL RrLl RrLl
...and accent the doubles or singles within different paradiddles or other rudiments:
RllR lRRl RllR lRRl
LrrL rLLr LrrL rLLr
Finally, practice doubles around the kit. A basic beginning idea could be to keep your right hand on the floor tom (if you play a right handed kit, that is) and alternate your left hand between the snare drum- first tom- snare drum- closed hi-hat. Then incorporate the bass drum. Again, use this basic double pattern as a starting point;
RRLL RRLL RRLL RRLL
Once you get the hang of it and feel your strokes are even, the possibilities are endless. Best of all, patterns and accenting those patterns around the kit makes learning FUN!
