Travel! Fly or take a road trip!
The worst thing you could do is to coop yourself up in one spot all summer. You'll just end up getting cabin fever. Take the opportunity to get out and see the world. Not only is this refreshing for your brain, but you'll probably end up getting a slew of new ideas. Heck, when I went to Rome a few years ago, I must have thought up of a half a dozen new book ideas that are still currently churning in my "to be worked on" part of my brain. Just discovering new locations is sure to spark something in you.
My next goal? Head over to Easter Island where my newest MG, LUCAS PEREGRINUS and the ESCAPE FROM MANUKI ISLAND takes place.
Just don't forget to take something to write down all your new notes...I've neglected to do this a few times, and lost some ideas in the waves of time.
This ties into the above, but seriously do NOT stay indoors all summer during nice weather just because you are trapping yourself behind a computer monitor. If you don't have a laptop or a tablet, invest in one. Use it to get out of the house, and at least write in some nice weather. You don't realize how refreshing it is to sit out on the patio and get cracking on some revisions while sipping on a nice Arnold Palmer.
Except when the mosquitoes come out....then they must die....
Dine out and hang out with people you haven't seen in years...lol
Grab your friends, and go for a bite to eat. Seriously, stop eating all that fast food junk just so you can eat quick and go back to writing. Sit down, and have a real conversation with your friends and family. They don't even know you exist anymore because you have secluded yourself to the editing cave.
No joke, you need to be social. Human contact is absolutely necessary to ensure you don't drive yourself mad. I've noticed the more I trap myself in my cave, the worse I become, so I be sure to at least hang out and see some pals at least once a week. It's a major brain refresher.
Talk to people about your projects
Tell them what you're working on, just so you can get some quick feedback. Don't necessarily look for criticism, just try to get a general sense of what a person's interest may be. Talking about your project out loud, may also help you figure out if what you're doing makes any sense!
Don't keep that stuff bottled in.
Finish up some projects that you put aside
Instead of jumping from project to project, take the opportunity to just finish up one you have been working on. The sense of accomplishment can be insanely rewarding. It can just be editing a chapter you've been neglecting, or finishing an outline, or heck even completing a novel! Every thing adds up to having a feeling of success. Makes you feel like you're actually getting somewhere!
Vent your writing frustrations
Do it. Complain to someone. Complain to everyone. Tell them what's bothering you. EMBRACE YOUR WRITING SOCIETY!!! We're all in this together, and we love helping one another, so vent away.
Just don't punch Marty Moose.
And heck..if you don't want to write anymore this summer, guess what. YOU DON'T HAVE TO!! Take a legitimate vacation and put writing aside. Come back fresh after a few weeks or even a month. It helps more than you know. Give your poor, little brain a break.