This one had me confounded at the beginning. Still sorta does, but I found this kewl online birthday calculator that will help deconfuse the process.

Check out the skills on this page by moving your cursor over them. A little popup box will give you details on that skill. Once you find one that you think will suit your race (yaoh, shen, ren) click on it. It will tell you what skills you get at the next three lvs. Pay attention to the race and the birth date at the left-hand side of your screen.

To get back to the original page, reload the page.

Here's the link for the Birthday Calculator.

A note on the Zodiac Signs: from what I've read on the forums to date, they mean squat. Rumour has it they will mean something down the road. So choose w/e for now I guess.