When I went to CDL07-08, i got my tickets by going to the reseller shops in Shibuya and Ueno. I had some friends in Japan who were going to buy tickets at the official ticket release date, but they waited until 2hrs after the tickets were released, so by the time they got there it was of course already sold out!
It's really easy to get tickets in the reseller shops, but you need to do research in advance if you want to get good seats. You basically need to get hold of maps of the arena (for Yoyogi this is easy, since it's posted in immel's thread) and then decide whereabouts you want to sit. Then you go to the reseller shops and see whet they have.
Keep in mind the prices will seem completely random and also sometimes be completely ridiculous, so you need to consider how much you're able to pay for the ticket and sometimes compromise the location for a better price. My seats were on 2nd floor H block, and I paid 20,000 yen for each. The most expensive seat was 1st floor K block, row 2, which cost 100,000 yen for a single ticket
Also, it was confirmed by a team ayu member in a previous thread that TA members also get random seats. So there's no reason to join TA for good seats only!