Wheelbuilding Tutorial

Edit: I made a simpler version of this tutorial here.
First you'll need a hub, rim, and spokes of the correct length. There is a spoke calculator spreadsheet online (spocalc) if you don’t know which spokes to use. I recommend building a complete practice wheel before making one that someone is actually going to ride on. Having another (new-ish) bike to estimate final spoke tension from is a big help. These are the basic steps. More detailed information is available on Sheldon Brown’s website.

1. Check that all the spokes are the same length by standing them up on a flat surface, picking out any that are too tall or short. Slightly mismatched ones make life a little harder for you later on. If the hub has been previously used, try to follow the indentations near the spoke holes as you lace the wheel. Make sure the rim is straight by laying it on a flat surface. Minor imperfections can be bent back into shape.
2. It is customary that rim labels are readable on the right hand side, and that the hub’s label should face the valve hole (not really necessary, just for looks). Important - Spoke holes are usually offset for each side of the hub, so a hole that’s closer to the left will be for a left side spoke.
3. Start by dipping the spoke’s threads in grease. Vaseline works fine for me, you can also use linseed oil (recommended) or special spoke prep (stupidly overpriced). Now lace the first spoke through the hub, following any existing indentations. For example, if there is a notch on the outside of the flange, thread the spoke from the inside of that flange so that the spoke’s elbow will sit inside of that notch.
4. The first spoke is most important. Start on the right hand side, lace a spoke through a hole in the hub from the outside in. Then connect this spoke to the rim by lacing it through the hole next to the valve hole. Screw a spoke nipple on top, leaving a few threads showing. Make sure that the hole on the rim is offset towards the side of the hub that you are working on.
5. The rest of the spokes will be laced in 4 groups. Continue lacing the first group the same as the first spoke, skipping 1 hole on the hub flange and 3 holes on the rim. Make sure each spoke goes into the hub the same way. Once the entire group is laced, check for errors: there should be 3 empty holes (not counting the larger valve hole) on the rim between each spoke, and there should be an empty hole on the hub between every spoke. Each spoke should exit the hub on the inside of the flange.
6. Now you can start lacing the second group. Thread a spoke from the inside of the hub outwards. The spoke should now exit the hub on the outside of the flange. This spoke will go in the opposite direction of the previous group, and will determine the crossing pattern. Most wheels are built with the spokes crossing over 3 other spokes. This is called 3 cross lacing. 4 cross is also somewhat common, as is radial lacing for the front wheel. Angle the new spoke so that it crosses over the correct number of spokes (if you don’t know then try 3 at first, if it is obviously too long and is sticking way out of the rim, try 4). The new spoke should be twisted around the last crossing spoke before entering the rim. This will create a more stable wheel. Connect it to the rim with a spoke nipple, skipping 1 hole between the existing spokes.
7. Lace the remaining spokes in the second group following the same pattern: spoke exiting on the outside of the hub flange, opposite direction of the previous group. Make sure every new spoke is twisted over the last crossing spoke, and make sure there is an empty rim hole between each spoke now. Congratulations, you’re halfway done lacing.
8. The third group should be laced from the outside inwards on the left side flange. You will have to bend the spoke around the existing spokes before connecting to the rim. This group will be built much like the first, angled in the same direction. Check that there is an empty flange hole between every new spoke, and that every 4^th hole on the rim is empty.
9. The last group will go in like the 2^nd. Lace a spoke through the hub from the inside out, so that the spoke exits on the outside. This spoke will be angled opposite of the third group, but in the same direction as the second group. Remember to twist the spoke over the last crossing spoke before connecting to the rim. Check for errors once all the spokes are laced. Now comes the tricky part.
10. Important - Turn every spoke nipple so that the threads are just barely hidden on each spoke. This is necessary for even tensioning.
11. Starting at the valve hole, tighten each spoke 1 half turn (or 1 full turn if they’re still loose). After one complete round, continue tightening each spoke in ½ turn increments. Check the wheel for roundness; hopefully it is still relatively straight.
12. Put the wheel on the bike (or a truing stand if you’re that fancy) and begin truing. This involves tightening and loosening spokes in bent areas in equal amounts (1/2 or ¼ turns for now) until the rim spins straight again. Use the brake pads to judge where the bent areas are. If the rim pulls to the left in one section, tighten the right side spokes in the bent area while loosening the left side spokes the same amount. Check any adjustments to make sure you didn’t overcompensate.
13. Once the wheel is true (doesn’t have to be perfect yet), add another round of tension. The spokes should emit a moderately high pitch when plucked.
14. Begin stress relieving by grabbing parallel spokes and squeezing hard (wear gloves). This stretches the spokes into a more natural shape and will prevent them from deforming as you ride. Stress relieving also prevents spokes from breaking later on (metal fatigue, physics, bla bla blaa). This is actually a very important step.
15. Continue truing/tensioning/stress relieving until the spokes become somewhat difficult to turn. They should emit a moderately high pitch when plucked. If they have been correctly tensioned, then all the spokes on one side should have a similar pitch.
16. Dishing: This step applies to rear wheels and front wheels with disc brakes. The wheel may be adequately tensioned and true, but the rim may not be centered within the frame. Dishing the rim involves loosening all the spokes on one side while tightening all the spokes on the other side in order to bring the rim towards the center. Start by tightening each drive side spoke (or disc brake side for front wheels with discs) by half a turn and loosen the spokes on the opposite side by ½ a turn. Continue this process until the rim appears centered. Check the dishing by flipping the wheel around in the frame. If the rim is still in the same place as it was before you flipped the wheel around, then it is dished properly.
17. Finish tensioning the rim. It helps to have another properly built wheel to use as a reference for the amount of tension needed. Pluck the spokes on the other wheel, and tension your wheel until the spokes emit a similar tone. Keep in mind that the left side spokes on a rear wheel will have a lower tone than the right side due to dishing. Important note – as spokes become tighter they tend to twist about 1/8^th to 1/4^th of a turn. You will have to turn an extra 1/4^th of a turn when increasing tension, and then loosen that 1/4^th after making the adjustment. This keeps the spokes straight and the wheel true.

Apply one last round of stress relief before final truing. To make fine truing adjustments, hold a brake pad steadily in your hand as you turn the wheel. Feel for pulses as the wobbly parts pass over the pad and true accordingly. Use 1/8^th turns on small wobbles. When the wheel spins visibly straight with no lateral or vertical hops, drink a beer.