Where can I learn about database design?

Im working on a project which will require database design, the problem is that altough I have worked with microsoft SQL server, postgre, mysql I have never been my self into a situation where I have to design a database model.

What resources do you suggest me to start learning about the topic?

The project consists in desining a data warehouse and then a multidimensional model for data analysis and DSS. But I want to start on the basics and when I have a good foundation start growing from there.

thanks!