my experimentation has never been particularly helpful, and it has often led me to make changes that look weird for reasons I don't understand (and in the past that has even turned me away from even trying to use makeup at all).

I've definitely relied heavily on others for help, e.g. as a beginner I needed help picking out colors that work with my skin tone.

Another way I see experimentation go wrong: I see a lot of trans girls with downturned eyes (due to testosterone shaping the eye that way) using heavy bottom makeup and low eyeliners - there's little awareness of the way this increases the downturned eye look and how this draws attention to a masculine aspect of their face.

likewise with the common tendency to use heavy and dark colors for lipstick, which again draws attention to the usually masculine features of the chin and lips

learning that using nude and lighter pink lip colors helps keep attention away from my chin and jaw and allows my eyes to shine more was only something I learned from educating myself about makeup and watching guides

I really enjoyed Samantha Lux's guide in particular: https://www.youtube.com/watch?v=gr27PNh8D4E