Try one of the older series. Those are pretty easy to solve and straight to the point.
Try Beru's series, (Patche, Yuyuko, whatever their name is right now.) Touhou Raffles. Simple, fun, and decent prizes.
Try Ronald's series if you want your brain to be fucked.
Try Red's series if you want to become a puzzler yourself.
Try mine if... No, don't try mine. (If you want to, Touhou Raffu #47 still has a day left. Only 5 people have joined, so you have a great 16.6 percent chance if you join now!)