Spray a mixture of vinegar, hydrogen peroxide and dishwashing liquid over the floors.

For instance, a great question to ask a painter is how they like to paint pop corn ceilings.

The general idea is to renovate the kitchen with new cabinet & counter top; Update all the restrooms; patch up all walls; remove pop-corn ceiling, repaint whole house; re-sand and re-stain all the hardwood floor; some plumbing work; install can lights in all rooms; move some lighting fixtures; add/move switches and wire for Ethernet.

There's a mixture of both that is completely dependant on the individual investor's situation...goals, starting point, timeline, market, knowledge base, etc...

If you are willing to sit on a property for 10, 20 or 40 years, say leasing it to a corn farmer, you may end up doing well. 

Here in Shelbyville the most common crops are corn and soybeans .

As to "customizing" it for your buyer,  what happens if they want purple carpet and an eclectic mixture of wood and yellow tile on the floors...... then what?  

Unless already updated, your waste lines will most probably be a mixture of cast iron and galvanized, but clay is still a possibility, and will be at their end-of-life.  

Is there an adhesive or sheetrock mixture i can use on this small spot.

From what I've gathered, it's a mixture of getting in at the right time, being willing to sacrifice certain things (or having them be not a sacrifice at all), networking, and having the time to spend putting in some personal sweat equity.