I have one that I find useful, it's called "The Handbook of Academic Writing: A Fresh Approach" by Murray & Moore. It is mostly about style of academic writing, tips for being productive etc.
I also have another one I used a lot as an undergrad as it tells you what is required for different types of writing (e.g. what should go in an abstract) - it's called "Writing for Science and Engineering" by Heather Silyn-Roberts - it is obviously discipline-specific so I don't know if that's any good to you!!!