1. Find the Perfect Spot
Start with a room that has all the furniture in place before you decide where your art is going to go. Lean your artwork against the wall or place it on the ground and leave them there for a while. This will let you get comfortable with how the artwork matches the existing interior décor. It's not quite the same as when they're on the wall, but it will give you an idea.
Deciding how to hang the pictures depends on the particular wall. But, here are some design ideas to help you get started.