For the water and shock proof issues, I use an Otterbox for those times and it works great, did a lot of reading at the pool last year
For finding new authors, I simply browse through the categories that I like, check out the new releases and the best seller sections also to get an idea as to who's good and who's not. Plus most of the online dealers have where you can rate the ebook, that helps, and if the author has more then 2 books then they are usually decent. Oh and the price of the book "you get what you pay for" for the most part
Plus you can always start a thread here to find recommendations