So often, we try to push through.  "If I just keep working, I can get this thing done."  

Then, all of a sudden an hour goes by, and you are not accomplishing anything.  

I have been the queen of this.  I push through because I think I can get it done, but I have no more in me to give.  

I have learned that giving myself small breaks helps me feel so much better, have more focused little chunks of time, and helps me know when it is time to be done.  

These are great practices to use before you start a new task, when you need a break, at the start of a meeting, etc.