I agree with DC-8 to some extent.
Learn the sound of letters rather than the number of dots and dashes.
Once you memorise the sound of letters it will be a piece of cake. Then you could try numbers just for the heck of it
I used to "Morse out" all licence plates I was coming across on the motorway
I don't do it much these days lol but it certainly keeps your Morse current..
HTH