how exactly would one go about truingtheir wheels with out a truing stand?

Well you can pick up a miroura for under 40 on ebay. Or others, cheap ones. But you can probably devise your own. If you use rim brakes just look to see where theres more gap.

Use the bike frame.
Turn the bike upside-down, adjust the brakes to be close to the rim and start turning spokes.
If you have a hop you may need to remove the tire and tube before trying to fix (easier to see it).

Enjoy

You can use the nuts on the brake pads (flip them around) for your feelers or take an old spoke and bend it in an L shape (be sure to bend a round at the very end as well so that you aren't poking at your tire or rim with a sharp bit of metal). Tape the spoke to your stay or fork so that it will pivot outward when pushed by a rim defect.

Assuming you have rim brakes (cantilever, V-brakes...) you can use the brake shoes as a guide. You'll need to suspend the bike so the wheel is off the ground. As you spin the wheel, you can use the gap between the brake pad and rim as a measuring guide. This will determine side-to-side adjusting.

Clean off the braking surfaces on the rim then flip the bike upside down and spin the wheel. Take a sharpie marker and slowly move it towards the braking surface of the spinning wheel, the high spots will get marked first. Tighten the spokes on the side of the wheel oppossite of the marked surface ca. 1/4 turn. Repeat spinning/marking on the other brake surface, tighten spokes as needed. Clean off the original Sharpie marks and check again, if needed adjust the spokes again. This only works for wobble and not for out of round wheels.

P.S. A "Poor Man's" truing stand can be frabricated from a discarded fork and clamped into a vise. All you need to make one is the fork, some nuts and bolts and a few pieces of bar stock. (drill, file/grinder and hacksaw required for fabrication).

To check if the dishing on the rear wheel is right, flip the wheel around and see if it is still centred in the frame.

Speaking of dishing, I'm going to be building a wheel soon. I don't have a dish stick and don't anticipate getting one. Anyone got any tips for a home made gauge?

Once you have the spacers on the axle you do not need a tool to dish.
Put the wheel in the stand with spacers and make sure the rim is centered.
The dish will happen.

For truing, just use the brakes, tighten the barrel adjuster until it just starts to rub. True that out and tighten another click. Repeat. You can get it to less than 1mm.

I use a ruler or wrench on the seat stays to check radial runout.

Measure from the braking surfaces of the rim to the seat stays for dish. They should be equal.

Do all of these with the tire off. (unless you are just doing a minor truing) I do this by putting my bike on my trainer. It is a decent workstand if you don't mind siting on the floor.

Well I was hoping for something a little better than eyeballing it, especially since I'm not convinced my end isn't a little out of alignment. Although the first build will be for my mtb which is still pristine, so maybe it'll be cool.

Anyhow, I'm not horribly concerned since I do have a tensiometer (on order, anyhow) and it'll be single speed, so equal length spokes, equal tension, it should just center without too much thinking about it. But I thought it might be nice if I was going to the effort of building my own wheels.

In the rare instances I needed a stand I made my own(though I have gotten one for a killer deal now). Just take an old fork and an old set of brakes(minus springs) and fasten the fork to something like a bench or a board. The board is nice, since it allows me to sit down in a chair and do it more relaxedly. The frame is still the best way to know if you have the right dishing/centering.

Another trick is to put plastic zip tie around the fork blade for the front wheel and one of the stays for the back wheel. Cut the zip tie, but leave enough to be close to the rim. If you cut it a little long you can rotate it a little to get it closer or farther from the wheel as the wheel trues. It gives you narrower focus point than a whole brake pad, which I find makes it easier to true. You also don't have to mess with the brakes at all, so readjusting them shouldn't be an issue.

See my post above, MEASURE with a ruler or mechanics scale from the seat (or chain) stays to the rim. The distances should be equil. I would think that you want your wheel centered in the frame, more than centered on the hub.

I'd rather fix a bent frame than build a bent wheel to go with it. A frame can be re-set.

In fact, by the time I get around to building up a wheel for that frame I may already have it taken care of.

What's this about a bent frame? I am not band-aiding a bent frame. That would just be bad.

Flip the wheel back and forth in the truing stand as you're tensioning the spokes, keeping the rim as centered as possible. You really don't need a dishing tool if you did that.
Home made gauges are very easy to make. You can almost duplicate the real tool by using a length of 1 by 2 lumber (I used oak) and some long bolts and nuts.

put the rim/wheel in the fork, use the brakes and keep a good eye. you can build a wheel this way. truing stand unnecessary.

sd

This is only a last resort, because it is cumbersome.
Dish can always be checked by setting the wheel on it's axle on the ground close to a wall with the skewer removed. Push down on the side farthest away from the wall until it touches the floor and mark how high the wall side rises. The flip the wheel over and repeat the process, if the wheel is dished it will rise to the same level. Adjust the wheel until the marks are at the same level. Tighten the low side loosen the high side.

This eliminates the possibility of your stand being out of center and it will tell you if your frame is out of alignment also.

Thanks for the tip about the nuts. Worked like a charm.