QIt's really hard for me to say no. I'm pretty much a pushover and I keep ending up totally overwhelmed. What can I do to get more courageous in setting limits?
AUnderstand why you keep saying "yes," and then learn some skills to support a new approach.
The inner game
To think this through, find a time when you're calm and not feeling overwhelmed. Set aside any anxiety about all of the things on your plate, and focus on finding a lasting solution.
Then start to explore the reasons that you don't say no. These may include fear of angering or alienating the person who made the request. You may feel a sense of obligation in return for help you received. It may even be something you'd actually like to do if you had time -- that can be one of the biggest traps!
Taking things on when you don't have the capacity limits your ability to focus fully on the things you want to be doing. Understanding this impact will give you some of your most important tools. Envision the work you'd be doing, the quality you'd bring if you had more time, the people you'd be with, and experience the sense of expansion that you get from connecting with your vision.
Now, analyze your behavior. Are you impulsive and then regretful? Do you let yourself get cajoled? What are the characteristics of the people who are hardest to turn down? And notice your feelings when you do set limits.
Finally, observe the skills of others who effectively set limits. Make a list of the words and phrases they use, their tone of voice, and their body language. You can adapt these for yourself as a starting place.
The outer game
Like any skill, you'll have to practice, and that's easier to do if you're not taken by surprise. Anticipate times that you might be asked to take on a task, and plan your response. An excellent first step is to gather information: "Please tell me more about what you're looking for and when you need it," and then finish with, "I'll need to think about it; I'll let you know by [time frame here]."
Use this time to think about the request. If you're the right person but are just too busy, you may need to go to your boss for prioritization help. If you have unique skills, consider countering with a more limited offer of assistance. However, you may just be another set of hands; in that case, you'll just need to take a deep breath and learn to say, "I can't take that on right now." People may ask you for reasons, and will try to coax you into helping. Default to the broken record technique: "It's just not an option right now." Keep a smile on your face, and offer to help again in some undefined future time.
Get support from co-workers, friends, and family who will help you stay the course. And reward yourself when you successfully set limits.
The last word
Take a deep breath and learn to say "no" so that you can say "yes" to the right things.