Said, Said, Said.
I used to struggle a lot to replace 'said' with more interesting, or more useful verbs. I find it helps if you write out a list of all the 'said' words you can think of. Read a book just to find the different words, and add them to the list.
I did this one night and I found that I had over 50 words just off the top of my head.
So when I need to replace a word, I just whip out my list, and look it over for something appropriate.