Turns out truing wheels is one of those maintenance jobs that is far easier than it sounds. Anyone can have a go at it with a couple of simple tools and some patience. In this video former pro racer Daniel Lloyd explains how to true a wheel using a high-end wheel truing stand. However, you don't even have to have one of these. If your wheel is just slightly wobbly, you may be able to true it to acceptable levels using your brake pads as a gauge. Obviously this will not be as accurate as with a stand, but it can keep things rolling (mostly) smooth until your next trip to the bike shop. Have a look.