The way Q made his bucks. Real Estate.
First you need to find a real estate agent and explain to him your plan. You must convince him that he will only make money on the sale of your houses and NOT the buying. He will most likely agree considering you'll be providing him with a lot of houses to sell. This guy or gal is key to your profit margin. He has to be good at what he does. Shop around until you find a good one.
Next you need a good contractor. Again shop around. Tell him your plan and convince him he will only be paid a percentage of the profit on the sold houses. DO NOT pay him an hourly wage. He will most likely agree considering you'll be providing him with a lot of work and the fact that he'll make more money on a percentage payout.
Now you need to get financing. This is the hardest part of the deal. However, once you've proved yourself on the first house, you should have no trouble getting ongoing financing. The key here is to get the financing without providing a down payment. Remember, you're basically applying for a mortgage and not a business loan. Mortgages are much easier to get then any other kind of financing. Banks nowadays are throwing money at people. You'll have to start small, therefore the amount of mortgage you'll need shouldn't be that much.
Note: This is one area the Q really did his homework. It was tough at first, but all it took was one institute to take the bait.
Now you need to find a house. One of the best ways is through personal bankruptcies and mortgage defaults. You may also try city hall for property auctions due to property tax defaults. You're looking for places that are run down and need work. This is where your contractor and real estate agent come in. They can help you to determine what house can be fixed up for the least amount of money and most amount of labor; usually cosmetic stuff, carpets, paint, roof, landscaping, windows, kitchen and bathroom. You must keep the cost of materials down between 5-10 thousand dollars if you want to make any money. This should not be that difficult considering the contractor can get materials cheap. Many second hand building stores will provide ample cheap materials at a fraction of the cost of new. The contractor can get it all on credit.
Next, you and the contractor work your asses off day and night to turn that pile of rubble into a nice house. It shouldn't take very long if you work hard every day. The real estate agent should already be setting the price of the house and lining up buyers. Try and do the outside first in order for the real estate agent to take pictures.
Once you've finished the house, it's now up to the real estate agent to make a sale. If he's good, the house should sell in less than 2 weeks.
And now you divvy up the profits.
This process is slow to start, however once you get enough capital, you should be able to get several houses going at the same time within 6-12 months. You should be able to pull in about 150,000 - 250,000 in your first year. The second year should get you to at least 350,000 or more and the next year about the same or better. Within 3-4 years you can make a million.
Make sure you get a good accountant that will keep your taxes payable to a minimum.
I should mention that your living expenses during this time should be kept to an absolute minimum. If you can live at home with your parents, great. If not, rent a tiny apartment for low dollars and eat a lot of Kraft dinner. You won't be spending much time at home anyway. If you can, buy a cheap pick-up truck to haul materials. You may not be able to do this until you've realized the profit from your first sale.
This system has worked for the Q and many others. It is no big secret. All it takes is the willpower to do it. And the Q did it before the ripe old age of 25.