My advice is to read, read, read as much as you can. If you buy all your books, highlight as much "interesting stuff" as you can.
If you go to the library, and find a really good book on the topic that you are writing about, read the books that are directly to the left or right of it on the shelves too. Thanks to the dewy decimal system, similar books are grouped together, so if you find one perfect book, chances are the ones next to it will be great too. Its a fast way of doing extra research and everyone forgets it!
Also, if you are typing your thesis on a computer, always have a backup of EVERYTHING.
After every day of writing I would send an e-mail to my friends computer with everything I had written so far. That way, if my laptop broke, or I lost my memory stick or accidentally deleted something I wouldn't have lost everything.
I wrote my thesis for my Bachelors and my Masters and now I'm a professor, and its amazing how many students don't back up the most important document they have ever written.
hope this helps