To fix branches on an artificial Christmas tree, you will need to start by identifying the problem. If the branch is simply loose, you can use a piece of wire to secure it to the frame. If the branch has broken off completely, you can use a hot glue gun to reattach it. If the branch is bent or twisted, you can carefully straighten it using a pair of pliers or wire cutters. Be sure to check all branches for damage, as some branches may need to be removed and replaced entirely.