Don't try for speed. Trying to get speed before you have control and accuracy will just give you an unhappy bucking horse that misses or slams in to barrels. Work on technique. Get those nice tight turns. Make sure you can ask for a stop at any point in the pattern. Don't always set the barrels up in the normal triangle. A good way to set them up is to make 2 lines with plenty of space between the barrels and work up and down the lines with direction changes, skipped barrels, double turns... thrown in randomly. Keep asking for every combination of turn you can think of. The second he starts to feel too loose, rushing, or out of control make him stop. Keep him there until he stands still to a count of 3 and then begin again. Do it at a walk, then a trot, then a canter. By the time you are done you won't have to try for speed. Speed will just happen if the horse has it in him and you won't have messed up patterns with penalties or even NT like all the people who concentrate on speed too soon. Half of them their horses don't even have the balance to do the pattern correctly much less at the speed they are trying to get out of them.