Let's me tell you my experience with promotion challenges in the forum.
At specific period, and specific rank challenge, user has to face with very different challenges.
For Junior Member rank, the challenge is you don't know what to do, and feel like it is impossible mission.
Lack of knowledge, vague understanding about the structure of forum, rules, guides, and even don't comprehensively understand about merit, merit system and the role of merit in the forum. So, it is always the most difficult to try contributing and earn your first merit.
During those most un-knowledgeable period, even hard-working contributions sometimes likely stupid things, or at worst violate plagiarism.
Most users probably plagiarise to show contributions. When they decide to stop complaining, and show contributions, they switch to plagiarism. Maybe due to their laziness or lack of knowledge on forum rules.
Next rank, Member.
Challenge for the rank probably remains too difficult, and sometimes you might still think it is impossible mission. Regardless the fact that you maybe more familiar with forum structure, rules, boards but the way you read, understand, then express your ideas through writing is still foolish, or vague. No one understand what your wrote, what you want to discuss with, or your posts simply out of context, and no one pay attention on such off-topic posts.
Over time, you will improve better, then move up to Member rank.
Next ranks, Full Member and above.
Yeah, from Full Member and above ranks, the journey for each rank is too distant, but I believe who can move from Member to Full Member will feel happily with their promotions.
In addition, they probably feel their lives in forum turn out to be more comfortable.
Comfortable in so many aspect, such as in the way they find information (by search for available topics, answers, solutions), in the way the read, understand, write to express ideas and contribute to discussion, and - of course - in the way they receive merits.
I believe that from Full Member rank and above, challenges are still challenges, but those challenges are not too hard, or impossible, or put users tired too much. From the rank and above, the matter is just time, and how long they will finish their challenges.
In a summary, I thought you should write your new topic, in which share your tips for the latest promotion.
I might do it when I become a Senior Member, maybe months later.