I've had a couple of days to play around in this, and I have some general tips for leveling quickly and surviving longer:
1) Be a mage.
2) Don't not be a mage.
3) Don't hang around the starting city thinking it's the easiest place to fight stuff. It wasn't for me.
4) Some monsters give better EXP for their difficulty than others, and you can't always trust the colour of the name label. Some red-name mobs are a cakewalk and give great EXP. Some white-name mobs will trounce you. Experiment.
5) If grinding makes you weary (as it does me), don't grind. Explore. I love exploring, and I just kill stuff along the way. I don't feel like I'm grinding that way, and I get to discover cool new areas, biomes, and creatures as I go.
6) As a fire mage, your regular attacks will occasionally cause a glowy swirl of fire around you. This is your 'free' power attack, so your next powerattack will cast instantly. Use and abuse this; it's AOE and has a decent chance to knockdown*. Great for groups and bosses!
And just for funsies, here is me riding my chocobo.
IT'S A CHOCOBO DAMMIT!
*I'm using the fire 'spit' spell, not the crappy hard-to-aim tornado thing