Best advice I ever got: try to set aside a few thousand dollars in an IRA (a mutual fund for your retirement). Because you'll have 50 years for it to double, double, double, and double. Contributions are even tax-deductible -- and you can withdraw them penalty-free for medical expenses, education, and first home purchases.

Also, keep in touch with friends from college/high school. For career reasons, they can help you find jobs -- but it's also good for your mental health.