Turing can be done in the bike frame, using the brake pads as the gauge for left-right wobbles. Radial errors are harder to see this way, but it can be done using a spoke or something similar clipped or taped to the frame or brake caliper.

But any truing stand will make the job much easier. You could make a simple truing stand. My first was an old fork that could be flexed far enough open to accept a rear wheel, and spokes taped to the fork legs as gauges. Now that I have a proper truing stand, however, this job is a real pleasure.

One centimeter would make any wheel that effectively up rideable on my bikes!