Glass installation is one of those things that you have to develop a knack for. It took me a few tries to get the hang of it and now I can do it pretty quick. One thing that a lot of people overlook is the glass itself. A lot of times it is a bit oversize and won't fit right. If the glass is too big the seal will fight you all the way. It is best to cut new glass using the old as a template, or have access to a glass sander to size it down if it doesn't fit.
