Pro-tips I've learned from many mistakes:
Always ask on forums for value if a lot of people are pestering you for things. It'll save you getting ripped off, and people are good about helping.
Max every monster before +fusing it. Stats are way better!
You get element bonuses for fusing similar elements into the monsters you're fusing. Keep this in mind, especially during fusion events!
Shout often, and make your shouts more than just "A". A funny shout is a good way to become known, or to make friends. You can shout by going to a player's page, hitting shout, and commenting on their wall. It's a great way to earn summoning points.
If there's anything else you'd like to ask, please contact me