For masking, I would recommend the XXX Main Mask Kits. They work great. The link that HB provided is a really good article. If you read that, it should answer all your questions.
Here are a couple of tips that I would recommend:
---Trim the body first
---Clean the body w/ rubbing alcohol after trimming it. Then rinse off w/ hot water.
---Put the masks on properly & evenly. Plus make sure they are stuck down.
---Take your time and spray LIGHT coats! Allowing adequate time in-between coats. Since it's cold out now, you will need to give each coat a little bit longer drying time. (this is the hardest part)
Other than that, I really don't have any other tips. Let us know how it turns out or if you have any other questions.