Because it's much more complicated to install a ceiling fan than a ceiling light fixture, you might want to consider having your ceiling fan put in by a licensed electrician. Ceiling fans need additional support from above and need to be anchored solidly to a stud (fan rotation can work metal screws loose.)
To remove the popcorn ceiling, start by protecting all the surfaces including floors and walls that you do not want to get damaged or wet. Since water is used in the process be sure to turn off the electricity at the breaker. Use a garden sprayer or spray bottle if you don't mind refilling often and saturate the ceiling. Use a plastic scraper to remove the popcorn material. As a side note if your ceiling was installed in the early seventies it may contain asbestos. Send a small sample to a certified lab prior to removing. While removing the popcorn, chances are some the joint compound was also removed. To insure a flat ceiling refill the joints and any screw/nail holes with fresh joint compound. Let dry, sand and repeat, to insure a flat surface a skim coat may need to be applied. Prime the ceiling with primer recommend for wallboard and a blank slate is created.
As a final check when taping drywall joints, use a side light to check for smoothness. The light can be a halogen worklight, a troublelight, a lamp without a shade, even a larger flashlight. Hold the light close to the wall next to the joints in several places to reveal high and low spots, or bumps and depressions, that otherwise would be easily missed.
You can square up a wall before raising it by measuring from opposite corners. Assuming that both the top and bottom plates are equal in length, and that both ends are the same, the wall is square when the diagonal measurements are equal. Adjust the wall as necessary, then keep it square with sheathing or with diagonal braces before raising it.
When lifting a wall section into position, the bottom of the wall can slip across the floor deck, and even fall off. If you are short on help, a solution is to position the section as it lays flat, then drive duplex nails (with two heads) through the bottom plate into the floor. The nails will bend as you raise the wall to a vertical position. After securing, pull out the duplex nails.
Feathering is a term which means using a brush to paint around borders and corners. When used well this technique will produce a smooth transition between the brushed parts and the larger rolled surfaces. Some painters suggest that when you feather a ceiling, for instance, you should only cut in the border a few feet ahead of where you will roll. In other words, the best way to paint a ceiling is to have one person cut (feather) in and have a second person with a paint roller come up behind. This will insure that the paint dries smoothly.
Recessed light fixtures can be a major source of heat loss, but you need to be careful how close you place insulation next to a fixture unless it is marked. "I.C."—designed for direct insulation contact. Check your local building codes for recommendations.
Recessed light fixtures can poke into the attic insulation and create a pathway for air leaks. Caulk around them from below with high-temperature flexible caulk.
Ceiling fans should rotate counter clock-wise in the summer (to generate a breeze downward to cool you off) and clock-wise in the winter (to cycle the warm air that rises to your ceiling.) Do not be afraid to run your ceiling fan in the winter. You can expect a 10-15% savings on your heating bill. You can save up to 40% off your cooling bill in the summer.
Before you buy a fan, consider the size of the room you want to cool. A 52-inch fan is appropriate for a room that's 230 square feet or larger, while a 42-inch fan is appropriate for rooms ranging in size from 150 to 229 square feet.