There is no discrete rules as to what is constructive post, quality post, its totally just readers discretion but I see your current ranks helps too, if you are lower rank no matter how good your writing is there is no chance you get any Merit.
The merit you see given around it is mostly not because of the content is Meritable it is because they are friend and they exchange Merit between them.
I appreciate what you want to express. Even though you had quality post you won't be able to earn merit as soon as possible. All we need is our post don't need long just to answer instead we'll answer in one word on what do we need to have a good quality post is common sense. I'm sure it is understandable word. We don't need a long sentences or we may need if you join a bounty with characters needed like 100 chars minimum. There are lot's of answer what to do on how to create good quality post one of it is common sense like a mention and honesty is also one of it.
