What are some good books to read in order to improve my academic writing?
Different books work well for different people, depending on your natural writing style, how you think, and your writing process (long writing sessions or short bursts, frequent iterative revision to 'perfect' each sentence as you go, or drafting the whole thing and revising from start to end later, etc.). 

I recommend first googling "thesis writing tips" and reading reviews of the books that pop up in the results (on Amazon, etc.)

Also you might find some ready-made lists of resources helpful, such as this one from UIUC: 
http://www.library.illinois.edu/learn/research/writing_tips.html

In addition, there are some fundamental classics on general writing strategies that can dramatically improve your academic writing. One such classic is Zinsser's "On Writing Well" (http://amzn.com/0060891548).

You might also appreciate some one-off resources that offer advice about specific sections of a thesis, such as the literature review, methodology, analysis, results, and conclusions. Google "tips for writing [fill in section here]" and see what comes up. 

For instance, doing this for "literature review" brings up resources such as this handout, from the University of Toronto: 
https://ctl.utsc.utoronto.ca/twc/sites/default/files/LitReview.pdf

or this presentation from faculty at UCSD:
http://www.jacobsschool.ucsd.edu/student/student_grad/docs/How_to_Write_an_Effective_Literature_Review.pdf

or this page from the UNC Writing Center:
http://writingcenter.unc.edu/handouts/literature-reviews/

In general, university writing centers exist for the very purpose of assisting students with writing needs. I highly recommend spending an hour at your university's center perusing their resources and learning about the types of support they provide. Try a consulting session with one or two of their writing assistants and see if it helps. Often a 1-hr consultation can help to correct some persistent trouble spots. They can provide actionable advice on everything from the right 'attitude' (ways to motivate yourself to write and to structure your time accordingly) to thesis organization, to grammar and style issues.

With regard to technical aspects, a helpful resource would be the APA Publication Manual, now in its sixth edition. Proper formatting seems a trivial after-thought, but appearances do matter in the academe. How you cite authors in a citation, or what part of the citation you italicize, can jump out at your reviewers (professors or journal peer reviewers, should you choose to submit the thesis for publication - which I recommend) and either enhance or hurt the overall impression about the quality of your written work. Good luck!