I am going through this painful process at an advanced age. All kinds of things make it hard. I suppose the central problem is reading pitch (where the note is on your instrument) and length of note.

I find songs most trouble because they don't have a lot going on. Jigs seem best, they go 123, 123, 123 or in my mind diddly, diddly, diddly. Another aspect of jigs is a dotted note followed by a short note, this sounds like der dit.

If I look through tune books and find simple jigs with lots of 123 in the end the tune will come out of my Mandola.

Hornpipes and polkas have a simple structure. It helps to move from tunes I already have in my head to ones I don't.

I recently bought '110 Tin whistle tunes' Compiled by Claire McKenna and published by Waltons, ISBN I 85720 084 5. This has lots of simple tunes and lots a bit harder, it has finger diagrams, music and 2 CDs of the tunes played well, but not too quick.

Although I play the Mandola, the book has helped me to move from tunes I know to tunes I have to figure out, This has helped my sight reading quite a bit.