Investment on an index card

I read this somewhere, but no longer remember where. My vague memory tells me that one investment expert, Nobel prize in economy or something like that, once claimed that all anyone needs to know about investing can be written in an index card. And here is (with some minor changes) the list that index card contained:

1. Maximize employee pension contributions;
2. Buy inexpensive, well-diversified mutual funds (ex: Vanguard Target 20xx);
3. Never buy or sell individual security (i.e. stocks and shares);
4. Save 20% of your income;
5. Pay your credit card balance in full every month;
6. Maximize ISA accounts;
7. Pay attention to fees and thus avoid actively managed funds;
8. Make your financial advisor commit to a fiduciary standard;
9. Promote social insurance programs.

I actually have a couple of advice I would add to the top of this list:

1. If you have any debt, pay it before investing. The exception to this rule is a house mortgage.
2. Make sure you have some money easily and quickly available for an emergency (about 6 months of your monthly expenses).