Setting up a watercolor travel palette 1: selecting a palette

I started watercolor painting because it is much easier to carry with you during (work or holiday) trips, especially compared to soft pastels. A small palette with a limited amount of colors will give you endless mixing possibilities. Add a pencil, an eraser, a travel brush, a piece of cloth, and a small sketchbook and you’re set to go. I always bring some waterproof fineliners or a fountain pen with waterproof ink as well, because I find it easier to do quick line and wash sketches compared to full watercolor sketches. But how do you decide what watercolor palette to use?