Dragon Quest IX: Sentinels of the Starry Skies Tips

Liquid Metal Slimes in Bowhole (Lots of Experience)
Once you reach Bowhole, you can take part in an excellent way to get lots of experience fast. It is the best way to level your characters for awhile (maybe even until post-storyline areas).

Make your way to the end of the B3 area of the level (where the staircase going down to B4 is. Stand in the corner to the northeast of the staircase, facing the wall/body of water.

Monsters will begin spawning one at a time in the southwest corner of the area you are in. They will spawn, walk to the right, and another monster will spawn. Stand where you are until Liquid Metal Slimes appear. Run at them soon after they spawn (before they run away).

Keep doing this as much as you want and rack up tons of experience very quickly. But be patient, because the Liquid Metal Slimes do not spawn every time a monster spawns.

The LMS's have 7-8 HP, and do not run away as easily as they did in past games (none have run away from me in battle so far). Some attacks to help take them down are Metal Slash (Warrior-types), Needle Shot (Ranger type), and Thunder Thrust (Spearman-types). If you do not have these attacks, just attack normally and hope for critical hits to take them out in one shot.