Use the DT spoke calculator website if you're a novice. Measure the actual ERD of the rim at four places and use the average number (should be within +/-1.5mm with a good rim). Gradually crank up the spoke tension on the cassette side so that the end of the spoke with the highest tension is within 0.7mm from the end of the nipple (DT comp 2.0mm). It's a good idea to overshoot by 1/16-1/8 of a turn when tighening/losening a spoke, and recover by the same amount in the final stage of wheelbuilding. This will remove most of the spoke "twist".
Do not overtorque (spoke extends beyond the end of the nipple). If the rim is of good quality, then all the spokes should engage the nipples by the same number of turn, plus/minus 1/2 to 3/4 turn with the finish product.
Take the wheel out lay it on one side. Use your hands to apply about 100lbf total on opposite side of the rim. Work around the rim at each spoke (28x for 28h hub). Do the same to the other side of the wheel.
Another advanced technique is to true the wheel at a higher preload (cassette side) by 1/2 to 1 turn, then backoff by the same amount for the final product.
In general, a wheel that's true to within +/- 1mm will have more sloppy spoke tension than one that's true to within +/-0.1mm (assuming the rim is of good quality).