According to the veteran experience, shaving your hairline back about an inch would give you more convenience supposing you wear wigs uk most time. This is to keep sure that the real hair will not be pulled out by the glue and meanwhile to allow the bonding glue to adhere more securely. Then remember to use a wig cap which should be flesh-toned for a realistic look to cover over your hair.
After that you need to mark your forehead where you want your wig to sit on with something erasable, like a liquid liner. Bundling all the stray hairs that would be an obstacle for gluing is a wise choice. If it was your first time to wear a full lace wig, you need to cut the front excess lace around the wig, which is made for a natural look.
As a newbie, leaving half an inch of the excess lace will give you more chances to practice wearing in case you would encounter other issues next time. However, for those pros, they tend to cut extremely close to the wigs hairline for a more natural look. Starting cut near the ear, then all the way to the center then top. Then go to the other side and do the same until you reach the center.
Do not cut the hairline or baby hair! Or you would ruin an expensive wig. Folding back about one inch from the hairline, to expose where the glue will be applied to secure your lace front wig is necessary. After the preparation of the wig, you need to clean your forehead to remove the dirty, oil, or makeup which are all the hinder to stop the wig gluing solidly to your head.