What advice would you give to yourself when you were in your twenties regarding finances, career and affairs of the heart?

Great question. We spent a ridiculous amount of time answering it on TGOS 067 (about 57mins) http://www.twoguysoneshow.com/2015/05/05/067-f-buckets/
In thinking about this good, yet haunting, question later, I realized we forgot to cover some advice an older mentor gave me once, which might apply to all three areas: What you're doing (or not doing) in the present will show results in your life 5 - 10 years from now, so act accordingly.
For example, while partying, smoking, drinking and putting off life-changing or life-challenging decisions in areas like finances, career and affairs of the heart might not have a noticeable immediate impact, it's the decisions that you make in your 20s that are reflected in the status of your life in your 30s. I imagine this holds true throughout the course of your life. Just something to keep in mind as you make or put off minor decisions today that might have a major impact on your tomorrow.
Hope our responses help. If not, our bad.