What is the single, most effective piece of financial advice you've ever received?

[Alpha Trader]

The best advice ever is "Never take advice". Meaning, trying to figure it out on your own will be worth more than any advice you could ever receive. And once you reach that stage, you'll be set for life. But if you can't figure it out on your own, at least you'll know what you're worth!

 

[Michael J. Fletcher]

"Invest at least 10% of your money in your education and development."

 

[Alpha Trader]

I haven't read this, but it seems relevant to the OPs question:

http://chatwithtraders.com/the-one-thing/

*Note: It's an ebook requiring an email signup.

 

[learner2007]

When I was very young my uncle told me "Save every penny you can while your earning power is the greatest". And now I'm the miser that he was!

 

[achilles28]

Wrong for a penny. Right for a pound

 

[speedo]

It would be well for a trader to consider this...."You can't eat like a bird and shit like an elephant."

 

[garachen]

The idea that there are earning plateaus.

Roughly 50k, 150k, 300k, 1m, 3m, 10m.

And that moving from one plateau to the next usually takes doing something different or acquiring a new skill. Not just doing the same thing better.

 

[K-Pia]

It would be well for a trader to consider this...."You can't eat like a bird and shit like an elephant."

That's a more lively, illustrative, version of what Achilles28 said.
"Wrong for a penny. Right for a pound"

 

[Buy1Sell2]

Never risk more than 2% of TLNW (Total Liquid Net Worth) on any one trade/idea.

 

[i am nobody]

Always avoid margin calls.