I wouldn't say I'm an expert on the subject, but I have some things that sometimes work for me to get out of the reading slump. Hopefully it will help some of you, too :)
1. Don't force yourself into reading something. Even if you have a hundred physical copies threatening to flatten you when the pile topples over, don't try and push yourself into reading/finishing a book you're not into. You'll only make yourself miserable, and you'll probably end up not enjoying it. This leads to..
2. Read something that catches your interest. Feel like reading Harry Potter for the bazillionth time? Go for it! Anything that will help you get back into reading is the way to go.
3. On a similar note, you might want to read some short books. When you pick out the right ones, they read quickly and you'll feel a bit more accomplished when you finish them.
4. For me, it often helps to randomly pick something off my shelf. I can spend hours thinking of what I want to read when I'm in one of my slumps, because nothing really catches my eye - if it did, I probably wouldn't have been in that dreaded reading funk. In the past couple of weeks, I let Amber pick my books - she gave me some numbers, colors or a letter and I'd pick the first book that fitted the description. I ended up reading books I wouldn't have picked myself (at least, not at that moment), and I ended up really enjoying them!
5. Is there a particular genre that gets you back in the mood for reading? Pick up one or two or ten of those and read them. Adult paranormal romance is the way to go for me - it's my guilty pleasure and I've read a couple during the past couple of weeks just to get the hang of things again. If you're (mostly) a YA blogger, like me, you might be tempted to pick YA books even if you're in your funk. A change in the intended age group might be a good idea to spice things up!
6. Tried a book, but couldn't get past 50 pages? Put it away to try again later. You might really enjoy it later if you put it away now. Try another book. Can't get past page 40 for that one? Put it away. Just repeat that until you get to something that you're enjoying.
7. If you still don't feel like reading, don't. Take a weekend or a week off, watch all episodes of your favorite series, go outside, change things up a bit. Being in a reading slump is not the end of the world, but it can be annoying. Perhaps a break is exactly what you need :)
8. Maybe I'm the only one, but it works for me NOT TO LOOK at the Goodreads reading challenge progress bar. If it says anything else than "great work, you're ahead!" I get a bit frustrated, and frustration doesn't help me read.
The most important thing is to go easy on yourself: trying to force yourself into something doesn't really help you get any further and it might even make you dislike reading. That's the last thing you want to happen!
These tips are things that seem to work for me. If you have any tips yourself, please share them in the comments!