I've had two main challenges in all my homes: making small rooms feel larger, and making sense of secondhand purchases. My approach to both is using a few key colors that flow throughout the whole house.
Bold transitions, while dramatic, can make a small house feel choppy. Sticking to a whole-house palette helps me edit random yard sale purchases. Another benefit: if you move often, furniture can easily switch from room to room. You may already do this without even thinking about it.
From the hallway, I can look through the doorway of each bedroom and see my key colors repeated in different ways: