First off, it's not a good idea to either save the tips for last or do them in the beginning. What I recommend is to get the 3 tips of the layer you do first done as you do the layer; not before or after, but during. For example, if you have a U' u, you could just do a sort of slice move (the same as usual, but without turning the tip with the body), and that tip will be done. You usually won't even have all 3 of those tips unsolved, so that makes it even easier. Basically, solve the tips as you solve its respective center. Then, for the last layer, do the alg and finish with that one last tip. If you have an AUF, that's great, because you can do the AUF and solve the tip at the same time. You can either do that slice move I mentioned before, or if it's not a slice case, you can sort of wrist-turn AUF and then move your hand up the piece to solve the tip. If you have no AUF, you can just flick the tip either clockwise or counterclockwise like you would if it was a normal turn. Hope this helps, and good luck with the best event ever!