Buying land->develop may yield higher profit (miat42)

But at the same time will expose you to proportionally higher risk. If you are experienced, you rather buy a house and flip it when good times return.

The land must be in good location, preferably in existing communities built about 50 years ago. In that case, you don't need to be concerned with sewage, gas, and utility setup for the lot. If the foundation is big enough, you rather not tear it down. Build a big house on top of that. Of course, your county zoning must approve of your building height, width, depth and etc, the grading must also be appropriate for such structure... Overcoming zoning complicaton probably would be the first order of your business.

Then you may also need to see if any previous McMansion has already been built in your chosen community. If that situation is commonplace, then it would lend you much convenience. You also need to evaluate the rebuilding cost, from $90-$150/sqft. Generally, you want to choose an old community within very close proximity to city core, of course close to commuter train is a big plus, ensuring the neighbhorhood is upper income class..., this is not easy but definitely doable with good planning.