When you start to learn a domain, you are often confronted with lots of complicated information that is difficult to remember. Looking up this information — whenever you need to — in the original sources takes time and makes practicing your skills a tedious affair.
One of the nice things computer programmers use are “help sheets” or “cheat sheets”. For example, Wikipedia has a page with the most common commands for formatting text that give users a quick and handy reference. Similar approaches are commonly used in learning languages, for example, with tables that display declension in a concise manner.
This approach also works to facilitate creativity. For example, I started to take photographs of people and there is just too much to keep in mind when you are making portraits. I cannot remember everything, so I created my own help sheet for exactly this purpose.
I may not take it with me everything I take photographs, but it is in a place where I often look at it (my wiki) to remember the things I should keep in mind.
Sure, there is no substitute for practice, especially in photography. But, personally, I also found the creation of the help sheet (kinda like learning by design) and looking at it occasionally very beneficial for learning.