OMG Where to start!!!
As Jonathan said, its not all glam like the reality shows depict! And the costs add up FAST! One thing a lot of folks neglect to include in their analysis are the property taxes you are responsible for while you hold the property, plus utilities! And don't forget closing costs, realtor fees, conveyance fee (depending on your state the % varies). Also, unless you are an agent, a lot of the good buys are gone before they even hit MLS - and when there is a bidding war on a low valued property, ENSURE and INSIST on have the seller initial your OFFER. That is the ONLY way to guarantee they even saw it. A good buyer agent will ask to do the offer in person to the seller to ensure you are fully represented! So after ALL those fees, then you can focus on the cost of the rehab - and realize, buyers are savvy and know the difference between quality workmanship and crap. Don't cut corners, it may save you a few dollars in the short term, but you will be wishing you spent them when your prop is still on the market at day 60! So now you've gone thru the "cosmetics" Kitchen remodel/bath remodel/opening up the floor (and don't forget the cost of the "supporting beams") , new flooring, paint, smooth ceilings; don't neglect the structural aspect and exterior - electrical upgrade? Plumbing upgrade? Condition of heating/cooling system, chimney repointing, gutters/siding (oh does the house have lead paint on the exterior - that's a nightmare!); driveway, sidewalks, steps, decks, patios. Is your basement dry? Now how about the landscaping and tree removal? It adds up - we've looked at 50 properties all of which appear great on the MLS until you start digging and find these things.
So besides knowing your market - the 1st thing I would suggest if you don't intimately know, is to bring a general contractor with you upon inspection of the home and start adding up the costs (plus the cost of the money you are borrowing, monthly interest, points etc). You will soon find out that once said and done, it may not be worth your while. Get yourself a good investor friendly realtor and general contractor!