(Ah! It's time to repeat what I have said several times before on similar topics — quick quota filler!)
If anything I have learned during my stay here with my account is, is perseverance is what counts, even if you think you ain't a good poster — have a goal to make a number of comments every single day (it's not that deep as it may sound), and make 'em on topics where you have something to say, merit will likely come, though I make no guarantees — just to wipe my hands off.
I don't think the bolded part of your statement is a good advice. Why should anyone have a goal to make a number of comments in a day? It will make interaction look mechanical.
I tend to do better with certain things to do in a day than having no direction. So, I prefer this way. It has never made things mechanical to me — if you have nothing to say and are forcing yourself to say, now that would be mechanical.
It is better not to have a target, this is because a day will come when you cannot meet up your target and that little push to hit the target could be the definition of the spam we all talk about.
I usually get this feeling, 'Dayum! That looks spammy' — in those cases I don't press, 'post' button. I do have targets but they ain't stringent, if I didnt manage to complete in a day, I move on and continue with next day and it's target.
Though, whenever I don't achieve what I intend meself too, I tend to feel like shit. So, to avoid that feeling, I try my best complete what I set meself to go through.