The virtue of a lace front wig is that the transparent lace lays over the forehead and allows the hand-knotted hairline to sit on top of your own hair line. In general, your goal is to ease the wig onto your head, letting the lace front settle down onto the forehead. Then check that the wig is sitting on your head straight – it should be the same distance from your ears on either side and the temples or sideburns should be level with each other. Once it is sitting correctly on your head, make sure the lace front is all the way down on your forehead, and that the knotted hairline is at or just slightly below your own hair.
You can pin the wig to your head if you have hair under the wig or a wrap on your head to secure it to. Otherwise, you can simply apply tape or adhesive to the lace front, the temples are generally the best place to do this. Lift up the lace edge, brush on adhesive or apply tape, wait a moment for the glue to get tacky, and then press the lace firmly into the glue, using a foam sponge or piece of silk to keep your fingers from sticking to the glue or tape. You may discover that the fit or style of your wig does not require gluing or taping the lace down.