I have an Apple Pro 13-inch laptop tied to a wireless Apple Magic Trackpad, wireless Apple keyboard, 2-TB external Apple hard drive, Apple External either-net modem tied with an Apply HD 27-inch LED-backlit display with built-in, high-speed Thunderbolt I/O. The system has worked amazing for several years. Until recently that is when my external wireless Apple Magic Trackpad starting skipping and became difficult to control. I tried many things to fix this and came upon a suggestion that sounded strange but worked like a charm.
I switched the language preference from English to Spanish and deleted the English preference. This requires a full reboot. Then I reversed it back to English and removed the Spanish. After that final reboot, my trackpad worked like it was brand new and was back to its amazing smooth self.
While I cannot explain why this fixed the problem I am left to believe that resetting in language means it was some kind of a software glitch which self corrected by switching language preferences. It certainly is not hardware or interference from anything else.
I hope this same workaround helps you solve your trackpad issue.
Dave