If I had to list financial lessons for most Americans they would be:
1. Pay down high-interest debt. Nowadays that's 5%+. Anything above 10% is an emergency.
2. Save an emergency fund: 2-3 months living expenses. Put most of this in a high-yield savings account earning ~2% interest.
3. Look at retirement savings plans that are advantageous for your taxes. Tradtional IRAs, Roth IRAs and employer-match 401ks are a few places to start. Try to save at least 15-20% of your income this way.
4. Great job! Continue to build your emergency fund (to 4-6 months), pay down moderate-interest debt (3-5%), and contribute to retirement accounts.
5. Put extra cash in stock and bond index funds in a taxable account. You can use this money anytime but its value will fluctuate (hopefully growing long-term).
6. Saving for a house? Sock more money in that high-yield savings account to hit a 20% down payment for a home mortgage.
7. Now you're ready for OP's life lesson #1. Buy a house you can afford and keep saving.