lol don't think too hard about it - you're supposed to be giving pleasure, not preparing for an exam! The best way to massage her breasts is to ask her how she likes to be touched. You can discover a lot by asking someone what they like and then tailoring your approach by observing their responses. With that said, here are a few general tricks:
1. Take her breasts in your hand and gently squeeze them. You can also kiss all over them and just discover different ways to hold them (cupping each one separately, squeezing them together).
2. In terms of nipples, there are a lot of choices. Flick them with the tip of your tongue or finger, suck on them, bite them (ask before you try this one), squeeze them between your thumb and pointer finger. You can even gently roll one from side to side between your thumb and pointer. (Warning: Don't focus all your attention on the the nipples. While they are the easiest target, they are only ONE part of a breast.)
3. Let your curiosity guide you to new methods.