I hear tons of it. But here's one I follow always:

"No matter what, only take advice from those who've done it better than you." - Mentor of mine

Well, I am always out-doing myself, so I can give myself advice.

When going back to college in my mid thirties I told myself to :

"Never put off 'till tomorrow what you can get out of doing all together, but if you <i>have</i> to do it... then Do It <b>NOW!</b>"

Next...

hmm, i think some of the best "advice" i hear (which is not so much advice but oh well) is from quotes I read on the personalized google thing.
I enjoyed your advice though Rodak - quite funny. Ixz, your is more practical. I think I will work towards putting that into practice >.>

Prolly the best advice I have heard in a while:
Hakuna-Matata

and yes I am absolutely serious.

Here is something good. I heard this about some years ago

"Don't fight someone taller or stronger than you, you will be laughed at by your friends"