[studiofellow]

For choosing colors, I'd suggest starting with a palette from elsewhere. Just like Kuler as louhong mentioned. Starting with proven colors will be better than choosing from scratch. And that applies to everyone, not just you.

I think in your case, feedback and validation from peers will be essential. However you'll have a leg up on the rest of us. Designing for accessibility is a challenge you already understand better than I do.

As for writing copy, there are definitely people more qualified to advise you than me!