Steve Gillman wrote a good basic article, Making Money In Real Estate - 10 Ways that outlines ways to make money with real estate. The 10 ways are:

1. Appreciation
2. Depreciation
3. Loan pay down
4. Cash flow
5. Buy Low
6. Sell High
7. Offer Financing
8. Change Use
9. Improve and Repair
10. Sell in Parts

The two points I find most interesting here are:

8. Change use. If there is a higher use for the property, you can convert it to make it worth more to the next owner. Sometimes this means making condos into apartments, or apartments into condos. Maybe converting a home into office space will get the biggest return.

AND

10. Sell in parts. In real estate, the parts are often worth more than the whole. For example, splitting off an extra lot to sell for $30,000 will rarely decrease the value of a home by that much, so you’ll make more money in the end.

Read the article if you’d like more details on the rest of his points.