How do you become a Grand Master vamp?

i've found that things such as researching vamps on the computer (even with max vampire lore it gives vampire xp i'm pretty sure), dark meditation, and asking grandmaster vampires in the game (ie premades) for training helps most vampires level up fairly quickly

You can reread the Ultimate Vampire Tome for more experience. Drink from sims, not from plasma packs or plasma fruit. Even Good Vampires can drink from sims as long as they get permission. Use Dark Meditation to restore Vampiric Energy. Use Vampiric Spar and Vampiric Training. Basically, just keep doing the things that got your vampire to the current rank and the rank will keep increasing.