You might want to check out Dave Platt's Black Arts video series. He has a three volume series called Building and Fiberglassing Techniques. There are some websites that cover the topic as well.

http://www.daveplattmodels.com/Videos/index.htm
http://www.arts-hobby.com/fiberglassing.htm
http://www.airfieldmodels.com/inform...nish/index.htm

The method I used on my current build and first epoxy fiberglassing, was to use primer. I used an automotive primer in a spray can, Duplicolor High Build Sandable Primer. I would spray a coat of primer, then wet sand with 320 grit until the high spots of the glass weave showed. I would repeat this process until I got a smooth and even surface. For gaps and dips that are too large for primer alone to fill, I used a couple of methods. On the smaller ones, I used spot putty that you can buy in a tube at the auto parts store. I applied it with a small piece of plastic. Those fake credit cards that come in the credit card offers in the mail work well for this. Be aware that this putty is pretty heavy. For larger gaps or dips, I used a mix of epoxy and microballoons.

Scott