There are some good books describing walks in Crete. Check the Books page for recommendations.
Below are a few popular walks with desrptions and photos to get you started.
Please make sure to also take a look at the page on walking safety in Crete. You might know it all, but then again, maybe not.
Additionally, if you are considering walking along the E4 (or part of it) take a look at the E4 : a long distance walk across Crete – the experience of an Englishman.