If the time has come to move on, make sure you leave a good impression in your final days.

Years of productivity and good performance can be erased or severely tarnished with an exit that is careless, shrouded in negativity, or lacking in the standard of confidence you have built with your supervisor or co-workers.  In other words, you can easily put your reputation at stake.

Have another job lined up.  You may feel that quitting your present job immediately will put an instant stop to the stress, anger, or other emotional issues that you may be facing with your current job.  The fact is it will only make them worse if you do not have another source of income to support yourself and family. 

Give timely notice with some grace.  Walking out or firing off an angry, "I quit" email message is not professional or respectful.  Allow some time to compose your notice and maybe have a family member or friend review it for underlying negative tones.

Be in control.  Show that you are making a positive move for yourself and offer constructive criticism if asked.  I have always found that you earn respect by being in control of your actions and destiny.  Speak and offer constructive remarks from a position of strength instead of a position of weakness that is perceived by remarks like, "I can't stand it here anymore".

No negativity on Facebook.  Airing your dirty laundry will bite you in the butt every time, in ways you can't even begin to imagine.  It's just plain stupid.  DO NOT do it!  For some good advice on protecting your online reputation, as it pertains to getting a job, look at this article.

Don't burn bridges.  In fact, try mending some fences!  You never know who you will work with or for at some point in the future.  Keep as many connections as you can in place.