General Tips For Every Room

Clean windows and all reflective or glass surfaces
Replace all burned out light bulbs
Remove cobwebs from wall/ceiling corners
Fix/straighten/open blinds and shutters (to emphasize natural light and views outside)
Make sure cabinet doors and dressers drawers close all the way
Make sure framed artwork and mirrors are not hanging crooked
Remove any small rugs that are not in great condition

Kitchen and Dining Areas

Remove magnets, artwork, photos from refrigerator
Remove any items from the top of the refrigerator
Put away all unnecessary appliances, dish racks, etc.
Make sure towels are clean and neatly folded
Clean stovetop and put away any pots and pans
Neatly organize any visible hanging kitchen utensils
Make sure the sink is empty, put all dishes and sponges away
Move calendars, mail, phone chargers, etc. out of view
Move paper towels, trash cans, pet dishes out of view
Remove booster seats from dining room chairs

Living and Family Rooms

Move any pet toys, beds, food dishes, etc. out of view
Hide TV remotes and game controllers
Hide exposed A/V or electrical cables, if possible
Straighten/organize books and DVDs on bookshelves
Place fresh unburned logs in the fireplace, if possible
Organize/remove pillows and blankets from couch and chairs
Remove any unnecessary furniture or exercise equipment (extra furniture will make rooms appear smaller in photos)

Office/Den

Remove as much as possible from desktop areas
Neatly organize any paperwork or items that can't be removed
Organize or hide computer cables under or around desk
Straighten/organize items on bookshelves
Move trash cans and shredders out of view

Bedrooms

Make beds, be sure all loose sheets are tucked in
Make sure any items under bed are hidden from view
Remove as much as possible from dresser and bedside tables
Make sure frames, posters etc. are not crooked
Consider removing children's names from the walls, if possible
Remove excessive stuffed animals and arrange or hide kid's toys
Move laundry basket out of view
Remove any temporary fans or space heaters

Bathrooms

Make sure towels are clean and neatly folded
Remove any used shower towels
Hide toothbrushes and other items from counter
Clean all spots and streaks from the mirror
Put a small potted flower on the counter, if possible
Move plunger, cleaning supplies, air freshener, etc. out of view
Move shower supplies out of view
Move trash cans and diaper disposal out of view

Exterior - Front and Back Yards

Be prepared to move any cars or trailers from driveway
Hide garbage cans out of view from street
Put colorful flowers near the front door, patios and walkways
Move pet toys, crates, beds, dishes etc. out of view
Move shoes, kids toys, sporting equipment out of view
Neatly coil or remove hoses and temporary sprinklers
Neatly arrange patio furniture and braai equipment
Trim and remove dead or discolored branches and leaves
Remove leaves from pool, walkways and patio areas
Remove pool sweep before appointment, if possible
Remove temporary fence around pool, if possible
Turn on waterfall ahead of time and clean leaves from pool

Helpful things to do

If there are pets - and they could knock over the tripod, or get into the shots - please try keep them out of the way for the entirety of the shoot.

I work around the house in no particular order, generally based on the light, but ideally I will not need to "move" people out the way as I work.