It’s all about the knowledge. Try to think about merits as a knowledge exchange: you give merit when you learn something new, you get merit when you teach something new, or you make other people think about something old in a new way. Once you progress in the knowledge you can start answering other users' question and solving their problems, or start contributing to  the forum providing new resources or tools, if you have the skills. Just try to figure out the best way to do so that suits your capabilities and resources.