You asked a similar question yesterday and you got some helpful replies with member trying to correct some of the misconceptions which you have about the forum and the motive people have for registering on it.
based on what I have read on some posts, merit is significant for us to increase our ranks, is this really true?
Yes, it is. Merit and activity score are combined to determine your rank, but you could have found this information with a little research. You would have also found the answer to the 'how you can increase your merit question' through a little research.
That is the reason you should prioritize knowledge first. Read and learn. There are many facets of this industry and exploring all will allow you properly utilize it.