Initially, I was to think merit is by chance ( i.e something that will just happen) or lengthy article ( i.e writing too many paragraphs and the rest of them), but I have come to realize that, it is more than that.
I have being discouraged several times because of my numerous posts and replies yet no merit then. Even now, some times I use to be discourage. However, the only way to get merit is by posting quality article ( that is what determines merit) which almost everybody is aware of now.
In summary, don't look at the quantity of post you have make so far but instead try to adjust, I mean improve in your posts, above all be consistent and patient that is the key.
Yes Obviously the quantity of the post does not matter rather the quality of the post matters a lot let's say you have written 700 words of a lengthy words post but it does not contain any informative material, Helpful material, or Interactive material so it will be counted as the shit post. Just focus on your post quality and improve it as possible if the senior members find/feel your post interactive/helpful/informative they will obviously appreciate your posts. All that is possible only when you will start to contribute in the Discussion on the Forum keep in mind my one advice here for you is that reply the post with informative material in such a way nobody has contributed like you in the same thread before you are replying.
Then the chances of Getting appreciated by the member will increase for you. On the same side, don't be demotivated so early as I have seen so many people who have made a lot of posts but their merits are too much less the thing is they are still participating in the forum and they are still motivated. Just keep the focus on Quality, not Quantity.