Ok i am a fairly short person 171cm ( 5 foot 8??) and the biggest problem i have with taller fighters is when they have very good legs.
Use your front kicks to maintain good distance. Semmy schilt is a good example of this and the way he destroyed Satake in Pride 17. If u havnt seen this go d/l the fight or buy the DVD its very good as a demostration how to use a snapping front kick.
Throw out that front kick from the front leg like a jab with snap to keep your opponent back and if u land with a solid hit even though its a snap b/c your a big guy and have heavy legs it will def hurt your opponent.
The only danger with using this kick extensivley is an opponent trying to take u down but if u perfect it with some really fast snap then it will go a long way.
Jabs are also very good. If u have a weak off hand then switch your stance so that your main hand is the jabbing hand and snap it out afew times to discourage your opponent from closing.
But honestly train your off hand up. Hit a bag with jabs only. Reapeat it over and over paying attention to your technique. Snap the jab out and pull it back very fast. Dont leave it out there hanging ofr someone to grap. Also snapping it back is good technique so u can protect the ribs when u lock your elbow back into position as well as your head from kicks.
It will be hard at first but the more u practice the faster, more accurate and stronger your jab will become.
These two techniques are killers for smaller opponents like me when i fight taller fighters in my dojo that have good technique.
An other very effective technique to maintain the distance is a very fast side kick from the front leg. No matter what stance u are in just snap the front leg out towards your opponents midsection that way u get the max reach rather then going high to wards the head which shortens the reach of the kick as well as slowing it down (Good for knocking someone out but the point is to keep your distance from what u are asking).
Lastly, Good foot and cardio!!
Bounce around left, right. back, dignally etc etc. If your fit u can keep moving indefintley snaping out your legs and hands in the way i have discribed above to keep you opponent at bay without gassing.
This will frustrate your opponent no end somtimes forcing them to make bad dissions in trying to close u opening them up for a big punch, kick, Knee or even take down.
I hope this helps u
