This tutorial will guide you through the steps involved in installing a new 240 volt 30 amp circuit and breaker. Although the thought of installing a 240 volt circuit may seem daunting, it is really quite straight forward if you follow these instructions.
The project will involve using two 10-gauge black hot wire conductors and a 10-gauge green ground wire conductor to complete this 240 volt 3-wire system. You will also need conduit and an electrical square box or switch box to house the wiring and new receptacle if you don't have those already in place.
For installations in a garage area you will need nylon covered type THHN wire conductors which are rated "oil and gas resistant."
You'll be working in the electrical service panel so I recommend you read the tutorial Anatomy of an Electrical Service Panel so you know what some of the terms used in this tutorial mean.
Remember, before doing any work in the panel, shut off the power to the panel! And if you need a permit from your building department make sure to get one!