Got a tip (or trick) on world building for a series?

We create a 'world' for each book we write. Stand alone stories end with a HEA, but a series needs continuity:

Setting details. Who lives where and how you get there.

 Character descriptions. Hair and eye color, build, choice of clothing and accessories.

Have you discovered a useful tip or trick to keep these details straight and organized? Easily accessible?   Modifiable?

What details are important to keep in a 'bible'?
A series could go on for years.