I can double tongue on one note, but say in like a run that isn't slurred, with many sixteenth notes that must be tongued, my tongue trips over itself and I can't do it!! And in the Suite in A Minor(Telemann) I have to learn how to do it effectively and smoothly. Any tips? I'm using the syllables
ti-ka-ti-ka, that is before i trip and fail. It seems that my fingers and tongue cannot work together when I double tongue, but i don't think thats the case. Help please!!!!

1)Start slowly
2)take your time to develop the coordination. Do it everyday occasionally.
3)Work on scales, etudes and pieces. If something has the same duplet note values, you can practice double tonguing.If a piece has triplet note values, you can still practice double touguing if you play each note twice. Otherwise, go to triple tonguing.
4)Do scales 4X on each note, then 2X and then finally one time.
5)Try using a metronome to control how gradually you increase the speed.
http://www.metronomeonline.com/
6)If you aren't doing it properly, it does not matter how fast you have the metronome. Don't practice mistakes.
7)Always work on your tone quality. Even on the shortest notes. Whatever you are playing, it's always about the tone.

you are getting good advice..I always have students learn double with short groups of notes, which you can do on each step of a scale for example..you can start with du-gu-du-gu-du on each step and then double the number of notes as you get more comfortable...

keep your throat open and your jaw relaxed, keep the tongue movement to a miniumum..