The proper dimensions for eBook cover images can be very difficult to ascertain, and are obfuscated by a great deal of misinformation online--even from Amazon itself. Matt Maldre offers an exceptionally useful post investigating this topic in detail--and providing precise pixel dimensions for a variety of reader devices.
Patrick Hester has developed a good tutorial on how to use the Scrivener writing software to compile an eBook.
If you can get past the (gaudy) delightful (gaudy) lavender background, you may find The Online Magazine for Fiction Writers to be a rich source of advice on varied topics such as word count, suspension of disbelief, world building and the naming of characters.
Different authors prefer different tools and processes for creating eBooks. Over at The Easy Way to Publish to Amazon’s Amazing Kindle the focus is on using Microsoft Word as a starting point. If you’re one of the many writers still using Word, the tutorials on this site may be of help.
Guido Henkle’s code heavy approach to eBook formatting is not for everyone, and maybe not even for me, but his detailed guide demonstrates how to create clean output that works across all major e-readers.
Practical Advice to Help Build Better Books offers detailed blog posts covering book production (both paper and electronic), the art and science of choosing fonts, and indie book marketing.
