It is really difficult to get merit not only for jr. member but also to everyone here because even there were a lot of quality posts, they were not merited maybe because the post was not recognized or read by users since there a lot of other posts in the forum. I think the best that we can do is to try very hard to make a quality post that can be recognized by many readers or users.
I think I know the threads that you are talking about since most of them are mega threads in the Bitcoin Discussion and Economics Section. A lot of posts there are not being read by the members since most of them are not really a good posts and already being said by the recent posts. I think if you will be posting there every now and then, be sure not to post on what the campaign managers call "megathreads". There is a lot of other sections here you can post where you can gain merit.