What seems like a long time ago I started doing the Times Jumbo Cryptic on Saturday. I had tremendous difficulty but found this site, where every Saturday there are threads about the same crossword and I asked my own questions.
I found it very helpful to get a notebook for phone numbers, with sections for each letter of the alphabet. Then, whenever I saw something I wouldn't have thought of, I added an entry under both first letters eg "judge" can mean "ref". So Judge = ref goes under J and ref= judge under R. Sailor has "tar" and "AB". "Con" is under "learn" and "study" as well as the suggestion to look for words meaning "criminal". And now "Y" under "gym". I still do this. Believe it or not "gun" can be "BB" in an American puzzle!
Over time the booklet has grown into something quite useful, though I no longer do that crossword (the relationship didn't last!!)