Well. That's life, kids. It's unfair. Punch the air and keep it moving.
Sometimes, you spend 18 out of 24 hours for 6 out of 7 days and not come up with a good idea.
Other times, you take a nap, watch The Laffalympics, eat some cheese sticks, and boom, you have an amazing idea.
It makes no sense really.
It's one of the most frustrating parts of the creative process, and something you are going to have to learn to accept.
That's just how it is. No matter how hard you try and how much you push, that great line or awesome layout or one simple connection to bring your entire campaign together - just will not come. (Jerk)
When you start feeling like a hamster in a wheel, take a moment to breathe and remind yourself it's okay - it may come later, or it may not come at all. But no matter what, it's okay.
Consider being stuck an exercise -- look at it more like running on a treadmill than hitting a wall -- and over time, you'll learn the best ways to deal with it and how to work your way out of it.
Also, you'll learn not to take yourself too seriously. The more you stress about not getting it, the harder it'll be to get it.
Step away from it. Take a break and go do something completely unrelated to rest your brain and ease your stress. Go back to it in a few hours or days with new eyes and new energy and see if you can make something happen now.
Do something different. Start on a new idea, new project, new way to stimulate your brain. Don't just fatigue yourself on this one thing that you want to make right. There are often several right answers. So start on something else, get your confidence back up and who knows, you may come up with something better than what you were stuck on anyway.
Work smarter, not harder. Sometimes it's not about how many hours you put in but how much you put into your hours. If you're working on this problem until 2 a.m. but you're hungry, tired or cranky, you're essentially wasting time. Eat, get some rest, refuel your brain and work when you're ready and roaring to go. Find out when you are most effective, and do the heavy-hitting then.
Crowdsource. Ask for a second, third, eighteenth opinion. Take their feedback + suggestions and see what you can add/change/omit to work your way out of this hole.
Know when to keep at it and when to let it go. Runners have that wall. So do creatives. Sometimes it just takes time. And sometimes it just doesn't come. Just rest, shake yourself off and start running in a new direction.
Oh, the joys of being a creative!