You level up mostly by posting responses to other people's threads. I've gained a lot of levels just commenting on patterns, and leaving a tab open on the site to collect my hourly bonuses (you can find these in the tasks section - there will be one for your specific level, and one "Everybody Hourly Bonus").
i'm here for about a year now and when you log in about 1 time a week you'll get to diy in about a year. The more you are active, the faster you'll get leveled up