The ability to turn on/off the lights one-handed (or with limited hand function) is important. Toggle, rocker, push-pad, or push-button type switches are all easy to use. Don’t forget about switches on lamps; they need to be within reach and should not require someone to perform twisting, pinching, or grabbing actions with their fingers.
The use of contrasting colors on the walls and switch plates help some individuals with visual limitations to easily locate a switch. Some switches are backlit or have built-in indicator lights, which helps too.