I assume you are talking mylar and not real metal tinsel. Make sure the hook shank has a smooth layer of thread under your wraps.Or if tail materials are on the shank wrap thread over it to make it as smooth as possible. Also using Christmas tree tinsel can be too wide for many patterns so the thinner material should wrap flat. Your wraps need to be constant. Do not over wrap then space it out.Practice just doing the body. After a couple of trys with the right size material it should come to you.