Do you have any advice for someone investing in real estate for a supplemental income?

How have you landed a great investment? I'd like to buy a duplex that has been in the newspaper's classified. It's 20k and needs TLC (15-20k work at most)-1 of the 2 apartments is livable. Average home price in this city is 50k. The duplex would easily rent for 400/month because it is also a college town.

Are you planning on living in the livable side? If so this makes it profitable to you as $400 would probably cover your payment with taxes and insurance escrowed. A place to live with virtually no cost to you.
Renting both sides, at least while you are working on the other side payment expenses would be covered and when finished would provide the additional $400 income.
I have rental property and not so much look for the income now as to farther down the road when everything is paid off. I have 11 s/f, 1 triplex, and 1 restaurant. Remember to factor in a vacancy rate although I would think in a college town you will fare better than others.
Do your due diligence work, research everything you can possibly think of and then some!!!
GOOD LUCK in your new investment career! I love it and can't think of any better way to create a future for retirement!