Speed is not usually a problem, at least for me. The real problem is _retention_. That is, specifically, being able to recall what I learned if I stop using it regularly for as little as even a couple of months. If anyone has some _real_ tips on how to improve that, please share.
Don't bother trying to remember details, especially about software: When you next need them, they will likely have changed. Instead, learn how to efficiently look up the current information when you need it.
Actively look for relationships between what you're learning and what you already know: Does the thing you're learning solve a problem that you're familiar with? Is its mechanism similar to something from another field? Does it achieve a similar result in a novel way? etc.
Write down these insights somewhere, and figure out some way to habitually review them. The details of this habit probably don't matter too much, as long as it's something comfortable for you to keep up long-term.
I usually write a quick reference/cheat sheet document for myself, first on paper, then move it over to OneNote. If I can find the paper version the next time I need it, great :) Otherwise I can look for the digital copy.
