Looming layoffs. Challenging kids. Aging parents. If you're like many people, you've got a lot to be anxious about most days. And like many people, you may be prone to worrying. "Anxiety is the normal human response to ambiguity," says Margaret Wehrenberg, PsyD, a clinical psychologist and author of The 10 Best-Ever Anxiety Management Techniques. "When we don't know what's happening, what's going to happen, or what to do about it, we feel anxiety. Worry is one way people try to resolve anxiety."

In reality, worrying does little to resolve anything and instead can cause health concerns such as stress and insomnia. Here's how to stop the worrying before it takes over your thoughts.

Consider what you can control. Whenever you find yourself worrying about something, ask if you have control over it. Can you control whether your company imposes layoffs? Are you able to stop your child from making bad choices? Can you influence what happens in the stock market? You'll quickly realize you have little control over many events.

Shift your thoughts. Focus on what you can control, and create a step-by-step plan to do something about what concerns you. If you're worried you'll lose your job, make a plan to beef up your emergency fund. If you're afraid Mom will fall, help her with ways to make her home safer. Taking action will help ease the worrying.

Create a replacement list. Write down a list of topics you can think about to replace your worries. Whenever you feel a worry creep into your mind, tell yourself to stop and replace your thought with something pleasant or productive. The thoughts can be about something like upcoming events—from a dinner out later this week to what you'll plant in your garden next spring. Or maybe there's a special memory that brings you instant calm. Just don't replace your thoughts with another worry.

Make a move. Next time you find yourself bogged down with worrying, get up and do something physical. Whether it's starting a load of laundry or taking a walk, the act of moving will help you shift gears in your thoughts, too.

Head for bed. It may sound counterintuitive to tell a worrywart to just go to sleep, since late-night fretting is a notorious insomnia trigger. But remember that nothing can fry your nerves or ability to think like being tired. To fall asleep despite your stewing thoughts, keep a worry book—a journal in which, a couple of hours before bed, you jot down thoughts that may keep you up. Then tell yourself, "I can't improve upon it today, so I'm not thinking about it." Some experts recommend kicking those worries out of the bedroom: Move the journal to another room and leave it there till morning. Make it sleep on the couch.