how do you learn some concept in programming/dev? am not talking about the understanding, but rather the remembrance part, like retaining in memory in a way that you could remember to recognise/use it , the next time you see it or need it?

do you prefer :
- writing on pen and paper(ie creating notes)
- writing a personal/public online blog
- implementing it in a project that depends on it/ some sample project
- or something else?