If you only believe 10% of what I say, then please believe this 100% - Do as much creative planning now because electrical work is cheap and easiest planned ahead compared to later adding on. I don't know what your skill level is, if you're surface mounting wire molding, fabricating metal conduit, internally fishing wire behind drywall all of which can change the picture of this project drastically. Always check your local electrical code even if you are not getting a permit. I hate electrical cords in a workshop space. Figure on over-head outlets for drop cord lighting, ceiling fan(s) and perhaps more lighting.
A good shop will have plenty of outlets spread out around the room no less than 12 ft apart (consider using larger gang boxes to accommodate multiple outlets at a single location. Before you begin, check your electrical panel box for available circuit additions, you may have to configure a sub-panel box for the garage and feed everything from there.
Because of abuse and frequency of use always use heavier duty outlets like those rated 120 volts rather than cheap 110 v. outlets. Yes to 12/2 gage wire for std. circuits and 20 amp breakers. Remember the use of GFIs where needed - don't overload circuits, add more ciruits. Consider installing a second 220/230 circuit - maybe someday you may want an oven for baking powder coatings, finding or needing a better (larger) air compressor that is 2 phase/220 v. a lift, a plasma cutter - I don't like to unplug and switch cords around because there's only one outlet. Consider wiring for Cable, Phone and speaker wires together with your new electrical work (I hate extra clutter) having a choice of location for another phone, Perhaps a TV and or a laptop. Perhaps you're not doing much of this at all but even small jobs benefit from careful planning and thinking ahead of the curve.