It's simple but need time. Writing constructive, creative, high-quality posts, then you will get merits sooner or later. The most important things is be helpful in the forum to help others solve their problems, or at least give them hints, links for more details, etc. Furthermore, merits will be given for high quality posts, but it's also a game of probability. Therefore, you should not pay too much attention on merits, just keep being helpful, you will get merits in the future for sure. Don't worry about merit points.
I agree with you.
And its true this is a game of probability. I have one merit that was given to me long without me noticing. this was way before i learnt that merits are given by other people who read or like your posts. Back then i was not posting anything other than just bounty submissions.
Today with posts i am struggling to accumulate the 10 needed to become a member but i believe a day will come and i will get the reward.