The easiest way I found is to put the tofu between paper towels or in a clean dish towel. Set it on a plate and cover it with another plate, and then put something heavy on top, maybe a can of something from the pantry. After an hour, the excess moisture should have been pressed out. If you eat a lot of tofu you might want to invest in a tofu press. Another method is to microwave the whole block of tofu for a minute, after wrapping it in a clean dish towel. Repeat several times, using a clean towel, and continue until the tofu is dry. Now this might sound counterintuitive but another method is rinsing your tofu blocks. After rinsing it, squeeze it with your hands and repeat until it feels firmer. Finally, there is freezing, which makes it easier to squeeze out the liquid. To do this, chop and freeze the tofu then thaw in a bowl of hot water or in the microwave, before squeezing out the excess water.