Learnt by just writing them down then pulling letters out of a hat and writing the . and - down. Weeks before the exam spent most of the time looking at things and then spelling them out in my head dit dah dah dit. Exam was in a room with about 15 others and some old duck turning on a tape recorder. All tones were played twice (fairly quickly) and you just had to write down the letter. It was all a bit odd considering that the IFR charts would have the Station name then below the morse code for the ident. Seemed a bit harsh to have to get the rating given the maps had the info anyway. Guess the law makers came to the same conclusion and eventually scrapped the morse exam from the IFR syllabus.