I can highly recommend using Zinnser paint as a primer. You will need fewer coats of the main colour, and it really does cover a multitude of stains.
You can buy disposable covers for the paint tray if you don't want to waste lots of water cleaning them (if you've used water-based paints).
You can tightly wrap a brush or roller in cling film and keep it in the fridge if you're going to be using it again within a couple of weeks - saves time cleaning!
Do a pre-paint wash of the walls with a sugar soap solution, then wash off with clean water (do this before filling).
Then just wipe down after final sand with a damp cloth, and vacuum before you start painting.
Move as much furniture as possible out of the room before you start, it's SO much hassle to keep moving stuff.
Put down decent drop cloths/ cover for flooring and anything you can't move out.
Start with the ceiling.
When painting a wall, start at the top and work down (to avoid any drips or runs).
Finish with a very light stroke/roll always in the same direction.
Depending on how high your ceilings are, buy a hop-up - so much easier then standing on a ladder to paint.
Again, depending on how high your ceilings are, and how much painting you're going to do, it might be worth investing in a small moveable scaffolding platform (I'll see if I can link what I mean).
You will be fine painting rooms, but the stairs are going to be tricky. You'll know from how the room painting has gone if you'll manage that, otherwise pay someone to just do that.
Good luck!
Edit: photos to follow