I had the exact same problem a while back. I did not find a good solution to it however.
After a while I realize that if you actually need to think about what effects to do most likely means you haven't practice or perform those effects frequent enough to be able to perform them smoothly for a spectator.
It is like playing sport or a music instrument, if you actually have to think about what to do, most likely you will not be able to perform the task to the best of your abilities.
With magic, you get one chance, and one chance only, little flash here and there ruines the effect and your image forever. There are no do overs. You will always have to learn how to transition form situations like those, but that's for a completely different topic.
So when all in doubt, don't perform until you are sure you're ready. Over time, you will be able to remember more and more effects to perform with out a real time aid. Practice, practice, practice.