Hope my response is not too late to be useful. Before I begin though, a few questions.
Are you painting the ceiling too?
How high - 17' for more?
Flat or cathedral?
Graywings' has provided a very helpful list. To it, I suggest a few additional items:
A wide blade knive to scrape all the "pimples" from the existing surface. This will minimize the potential for runs in the new paint.
A 5 in 1 painters tool to remove the compound from nail pops. Also a screwdriver and/or punch and hammer to tighten the screws or reset any nails.
A small container of compound to refill the nail pops.
Some drywall tape should it be necessary to replace any that has "popped".
Sandpaper to feather any fill areas into the wall surface.
A quality sponge to wipe all surfaces dust-free before painting.
Possibly caulk and a caulking gun. Use paintable caulk!
Visit your local rental agent for tools to assist. They have a variety of items for DIY'ers. Personally I don't like resting an extension ladder against my walls so a Little Giant type ladder (basically an adjustable 2-sided step ladder) will enable you to reach high and adjust to work on stairs too. Or, rent scaffolding - especially useful for cutting-in at the ceiling. Be Safe!
TIME! It took me a week to redecorate our entry. The final look will only be as good as the preparation beneath. My painting sequence (following preparation) is ceiling, then trim, then walls. After painting the trim and allowing a day or more for curing, I apply the delicate blue tape to create the clean edge for the wall color on the top edge of baseboard and against the door/window trim. Use an almost dry brush and paint against the tape for the first coat to dry and seal the tape edge and prevent bleeding underneath.
Hope this helps. Good luck.
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Paining tips
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