Even if I tried to contribute answers and suggestions in other topics, it is very hard to gain merit. Which topics require quality answers and comments while people really willing to give out merit?
The good news is that your posting history is not spam nor built from extensive bounty reports. Nevertheless, your posts need to be more elaborated in order to have a fighting chance, putting more thought/time/study into them. Also, I would try to avoid posting on mega-threads, since those are generally ignored by meriters due to the amount of spamming that goes on there (with few exceptions).
Apart, from guides that users have written on the matter, I would also look at the forums official statistics and see what kind of posts are behind those being merited:
https://bitcointalk.org/index.php?action=merit;statsHelpful threads:
Comprehensive guide to Bitcointalk. Newbie friendly + calculator and infographic. The posts date seems oldish and pre-merit system, but it has been edited and is up-to-date.
TMAN'S guide to getting merit