More adventures in knitting! I just figured out how to remember whether to knit/purl normally or through the back loop for each type of lifted increase.
You insert the needle from the side of the origin stitch.
So if you're lifting from a stitch on the right needle, you come in from the right (either ktbl, or purl). If you're lifting from a stitch on the left needle, you come in from the left (so knit, or ptbl).
The lean of them I find easier to remember. If you lift before knitting the origin stitch, you're adding it on the right of that stitch, so it will lean right. If you're lifting it after knitting the origin stitch, you're adding it on the left of that stitch, so it'll lean left.
For remembering M1R/L, I combined the tip I saw on nimble-needles (about halfway down the page there's a big "how to remember" titled section) that the front leg of the stitch should lean in the desired direction--plus my personal observation/interpretation of "knit (or purl) through whichever side is harder/more annoying to get the needle into because that part of the leg is shorter and has less room." (The site does include a way to remember the second half of the tip, but it's easier for me to internalize "more annoying" than "closer to the next stitch.")
This is gonna save me SO many reference tabs.