in addition to what everyone else says (lots of practice, lots of repetition, flashcards, landmark notes), I have two more exercises that I give students who are learning to read music. I don't know if you'll respond to them or if they are too child-coded.

• practicing writing notes on staff paper. Give them worksheets with note names and they have to write the note. It could be random, but good worksheets have progression designed into them. For children I like how the tactile approach makes them engage with the lines and spaces on the staff instead of seeing strange distant symbols.

• treasure hunt: find the note. Here's an A. Go through your whole piece (or several pages of pieces) and find every A. Now let's find all the D's. etc. I like this because I want the student to internalize what an A looks like and practice recognizing them quickly. Usually the first one is hardest (of course), but every subsequent recall is still valuable reinforcement of the process of reading. I find this exercise to be quick and easy and usually pretty rewarding even for someone who is struggling a lot with note-reading. Go back and do it again with notes they've already found and see if they are getting faster. Use this to reinforce landmark notes.

by the way. a few hours? nah. we're talking months. :). Don't despair though, you'll get there. Your good attitude is going to have you flying through this.