This one’s easy, because (I would hope) you’re already doing it: read! Read books you love, whatever they are. I won’t go as far as some advice-givers go, and tell you to read mainly books in the genre you want to write in. I think it’s more important to read books that captivate you for any reason. That way you’ll not only be enjoying your reading time, but you’ll hone your unique voice, which is fed by the specific collection of interests that only you possess.
When you finish a book, review it online. Goodreads is a useful place for this, as of course are Amazon and B&N and Kobo and iTunes and…well, wherever you bought the book would likely be a good place to review it, but mirroring the review on other sites is a nice touch if you have the time. This not only gives you a handy record of what you’ve read and what your impressions of it were, but it serves as a bit of marketing for you as an online book-related person. People might like your review and look up the stuff you’ve written.
THEREFORE: look, I can’t dictate to you what to do. But in your reviews I strongly suggest you avoid snark and trash-talk. If a book didn’t work for you, find the nicest way possible to say so, and even with those books, try to include a line about what your favorite part was. I mean, think about it: when you rip other people’s books to shreds, anyone reading your review is going to expect some pretty fabulous material from your pen if you hold such lofty ideals of literature. Can you live up to that? If you don’t, are you ready to get equally dumped on by people reviewing your stuff?
Now, unfortunately, people might trash your work even if you’ve been 100% nice in reviews. It happens. It hurts. It sucks. But at least you can take some comfort in having the moral high ground, which, seriously, a lot of people will respect you for. Be the class act.
Exception I will grant you: if a book has sold hundreds of thousands of copies and has thousands of heart-eyed five-star reviews, and you just don’t get it, you can say so a little more flatly. I admit I did this with the third Twilight book, for example. But even then, I recommend holding back from a full-out immature rantfest. You’ll thank yourself later.
Anyway, go read books! Enjoy them! Final hint: if you aren’t enjoying a book, don’t finish it. Stop halfway, DON’T leave a review, and move on to something new. There. Happier already, right?