Thanks for the pointers: resteemed.
Myself, I've tried to be careful with the tags from the time I got here. Even if there were no active effort like @steemcleaners , I'd still be expecting some kind of clampdown. :)
Here's a rule of thumb I settled on: the first tag should be the most popular tag that's relevant to the post. Look through the Tag List on the left-hand-side of the Trending page and find the tag or tags that are most relevant. To emphasize, don't look at the posts on the Trending page: keep your eyes on the left side of the screen at the tag list and select from there.
If you don't find any tag that applies, go to the larger tag list page and select from there. Pick the one with largest amount of posts and is relevant to your post content.
Example: if I were to write about James Burnham's theory of the managerial revolution I'd look for my first tag on the left side of the Trending page. As the page is now, there isn't any tag that fits. Seeing so, I open up the tag list page and select #politics: a good-sized category that's also relevant to the post.
Another example: let's say I've become a prepper and I write a post about the food I've stored and why. I look in both the left page and the tag list page and find nothing for #diy or #prepping . But I do see the category #homesteading. After a look at its posts, I see that simply blogging about the food I stored isn't that good a fit - but a post on growing,or processing, my own food would be. So, I throw the stored-food post into #prepping and make a note that I should write another prepper post about (say) buying food in bulk and then canning it.
The last example shows an advantage in choosing the best relevant categories after checking to see whether or not your post fits into the high-payers. Looking at the ones which do fit gives you ideas about what your next post should be about!
Great additional points!
It's easy for new people (especially those that haven't done content creation before) to know how tags really help them grow by getting themselves in front of their desired audience.
Many people forget that it's better to talk to a specific audience. There is very little information that everybody will be interested in.
Upped to hopefully get this topping the comment list. :)