You know what my friend no one from all of us here, not even the legends can give you the right answer to your question for how to earn merit. The only answer that can feed to you is make a quality post and don't expect merit, if you do this you will be save from possible upset emotion of recieving no merit for your quality post. I give this advice because I saw how the merit being misuse and abuse and become a discouragement of the quality posters.
Every person that avoids to expect merit but contribute in this forum is a big help to rebuild the beauty of bct which leads the possibility of removing the merit system.
Well, I think I'm just dreaming a lost paradise-like because you can see the real character of each individual who was and is involve of misusing and abusing the merit.