It's pretty common to feel overwhelmed in our daily lives with more things that need to get done than time in the day. The first way to deal with this is usually to prioritize. Determine what needs to be done and then start with the most critical tasks. Your list of "to-dos" should be about 5-10 major tasks to remain manageable. Try not to start new tasks until the critical ones are complete.
I'd like to suggest another method to help with time management, say no. I'm not suggesting being rude or skipping out on critical tasks. Be cognizant of how much you take on. Sometimes people struggle to tell someone no. The easiest way to do this is to be honest. Be honest about your time, commitments, and work-life balance. Some people don't want to seem rude or let others down, however, by over-committing yourself, you can often let people down just as easily. People are more likely to respect your honesty.
Its important to practice saying no at work as well as in your personal life. At work, you may not have the option to say no. You may need to agree to a task, but agree to work on it when it fits into your schedule. You can also look to delegate and find someone else for the task. Many times this presents an opportunity to help develop someone else. You may also find that someone just needs a little encouragement or advice and they can then do the task on their own.
Just remember, it's okay to respectfully and honestly say no. Successful time management can be critical to reducing stress and saying no is one tool to practice and learn.
See these links for tips for saying no in specific situations and more information
20 Ways to Tell Someone No
http://www.selfgrowth.com/articles/Creel21.html
Nice People Can Say No
http://www.selfgrowth.com/articles/nice-people-can-say-no
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