What is your technique? Do you have the person lying down or sitting up? Any draping?
Arms are not my fav, luckily I don't get than many requests. Women are much easier than men, that's for sure. The hair is much finer. Men or Women, I have them sit up, it's much easier to get at all the different angels and have the skin taught. No need for draping, it's just going to get in the way.
As for technique, I would start on the forearm and apply wax all the way around then remove. Just follow the growth pattern. Then do the elbows, then the upper arm. There is very little if any hair on the inside of the upper arm.
Hope this is helpful.
Sorry there is no magical way :) Not many people have their arms waxed, so that's a plus. Oh and depending on how you hold their arm, you might want to put some table paper in their lap just in case.