#1 Not for the faint of heart.  Emotional aspects of the process have to be left aside as often as possible.  Do not accept an applicant for an emotional reason.  
#2 Consider buying a property needing work, overlooked, distressed.  You can solve condition problems later.
#3 Look for a landlord moving on.  If you can buy a property with a tenant in place, then you are 5 steps ahead of the game.  Be sure to check all documents, procure all escrows, and be sure the management is transferring also.
#4 It is better to be empty for a month or two than to take ina risky applicant. 
#5 It is better to take less rent than the market will allow if you find a solid tenant or want to keep a solid tenant. 
#6 Property turn is the hardest part on the process.  Have plans in place to do repairs faster.  Having paint codes is a big help.  Cooperative tenants are a big help. 
#7 Befriend the neighbors and request a call if anything unusual is noted at your property. 
#8 Hire a property manager who is a member of the NAR.  Unless you are in a very flexible job, already tied to construction, remodeling, or a trade, you are not going to have the ability to solve problems in a timely manner.  Also the laws and proper forms are ever and always changing.  This will cost you, but if you look at the actual long term benefits....less down time, higher rents, fewer non paying tenants, better condition it is really penny-wise and pound foolish to do it alone. 
#9 Understand the financials.  You have different ways to look at your rental financially.  Look at the rental income, less your expenses.  Hopefully that is a cash-flow positive.  Expenses would be mortgage, HOA, insurance, taxes, management fees, and repairs.   Also look at the appreciation of the home.  It is important to get the property for the right price and not over pay.  That is why getting a diamond in the rough can be a good strategy.  
 #10 If you have a 10 year timeline, you can project out what your rental asset will be worth give historical appreciation numbers, say 5%.  In addition, your tenant will be help you with the mortgage and paying down your principal balance. 
#11 Consult a tax professional/CPA regarding the tax implications.  
#12  Convert a principal residence into a rental.  This is a common strategy I see with Military service members who may do this out of necessity.