Find mobs your level, beat upon their faces. Exploring with your "Lfg flag" up (for what good those do, but that's another matter) til you find mobs you can pummel over and over and over and over. Its very slow to grind solo. Everyone just PL's for the most part now, every day there are more complaints that there are no parties to get into. It is a justified complaint, too.

There are, however, at least a few resource sites that still have more or less updated mob info. As a general rule, just explore the areas around the camps that are appropriate to your level. I wish you good luck in finding a low level group, but if you have the same luck as other people who've been posting here you'll probably grind to 40+ solo.