I wish I had any good advice other than just "do it". Next time you need to make a meme, open GIMP first, and each time you get stuck trying to do something that you cannot figure out among the million submenus available, search online for how it is done. Most of the time, someone else has already posted on StackOverflow or something asking how to do that very same thing. Eventually, you will rely on outside help less and less.
EDIT: Just looking up "make meme with gimp" seems to come up with some good basic tutorials, though some are quite old and outdated. The one thing that I do not agree with in any that I had checked is their various methods for adding an outline to text. I like to use the Drop Shadow filter to do so. Select your text layer > click Filters (in the menu bar at the top of the window) > Light and Shadow > Drop Shadow. In the dialog window that appears, set the following values:
X: 0
Y: 0
Blur radius: 1.00
Grow radius: 10
Opacity: 1.000 (or whatever the maximum value is in your version of GIMP)
Depending on the font size of your text, play around with the blur radius and grow radius until it looks good to you.
I haven't really thought about it. I might resort to scanning the comments and doing a Bayesian score. Comments tend to use key words from the meme.
It's not for science; it doesn't have to be particularly accurate.
Also, mutherfuchers should annotate images with textual descriptions for fukcing accessability reasons, but they don't. That's something the Mastodon community does better the lemmy community does.
Oh, I missed the visor up at the top. That entirely ruins the joke I was going to make about its absence... So anyway, here's a bunch for no reason I suppose:-).