Determine the coverage area for each color and estimate the number of gallons you'll need for each. For odd walls with angled ceilings, make your best guess. If you're not comfortable doing this, measure the wall at its highest height and multiply that by its width. Now subtract the lowest height from the highest height, multiply that number by the width, cut that answer in half, and finally subtract that new number from the original height by width. That should give you the wall area.
Plan the workforce. If you intend to not hire a professional crew, you'll need lots of help. There are many jobs to be done. First there's the furniture moving, then wall preparation, floor covering, materials gathering and prep, cleaning, and don't forget everyone will have to eat. It can easily take a team of five people a full ten days to paint a two-story (approx 2000 sq.ft.) home. Get as many people to help as you can. If some can only come one or two days, great. Maybe others can fill in. Ensure you plan with your workforce members in mind. They'll need plenty of time to arrange days away from work. Identify a few key personnel:
A more user-friendly option is a water-based “latex” paint, which blends acrylic pigments with a thin base for easy application with a brush or paint sprayer. Although many water-based interior paints are promoted as one-coat wonders, there can still be a need for an initial primer coat followed by one or two coats of latex paint. Water-based paints are very low in VOCs, which means minimal odors during the drying period. Most spills can be wiped away without the need for chemical cleaners, and clothing containing latex paint can be laundered in water and detergent. Water-based paint is a good choice for first-time DIYers and their younger assistants.

Scale has one of the biggest impacts on deciding whether to hire painting help or take matters into your own hands. If you want to paint your home, consider whether or not this is a realistic task to take on yourself. For instance, is your house multiple stories or a townhouse? Do you just want to paint the kitchen or the entire exterior? Once you factor in the time it takes to do the prep work and lay down multiple coats of paint, a DIY paint job can get complicated. If the house painting job is extensive, you may want to leave it to professionals.
Painters will agree that you should always aim to paint in the part of the year when it’s least likely to rain, has low humidity, and when the temperatures are above 50 F. Rain can wash wet latex paint off a wall, and temps that are too low can affect the way the paint sticks to the walls. Some painters will add additives to the paint if working in very high temperatures to slow down the drying time.
The Cutters. Someone with meticulous attention to detail and a steady hand should be assigned the job of "cutting in," or painting a straight edge where needed, such as along a wall where the ceiling does not get painted. Many products are available to assist, but none work as well as a person who's good at doing it freehand. Ensure this person is skilled (ask them to show you). A poor, jagged, wavy or splotched cutting-in job will jump out at you every time you walk by it. Why more than one cutter? This job is nerve-wracking and painful to hands and arms after a few days. You'll want to give this person a break after a few walls.
Staining a deck costs $540 to $1,000. Covered porches might hit $2,000. Consider negotiating the price a bit lower by combining it with a full exterior job. Painting handrails can run anywhere from $1 to $2 per linear foot, depending on whether it’s wood, metal or some other material. Although you might think this is an easy $30 to $100 job, most painters charge a minimum fee regardless of the size of the project. You’ll probably end up paying at least $150.