The best housing investment option depends on your goal - are you thinking about cash flow, tax write of, equity build up, rent saving, fixer, etc?
The best way to get started is to talk to a Realtor who can give you advise on the local market you are interested in (rental properties, condos, single family homes), the prices, availability, whether it's a sellers market or buyers market for the specific type / price range, etc.
The Realtor can also introduce you to a reputable mortgage broker who will be able to analyze your income / expense / credit and give you advise on how much mortgage and monthly payment you can afford, which will be useful when determine what type of housing you should go with for short term investment purposes.
Yes - the longer you hold a house, usually the higher return you will be able to achieve. .