Database modelling

When we think of database design, we need to think of the following:

Table design:

• What rows will the table contain?
• What will the primary key be?
• Do we need to apply any constraints to any of the rows?
• How will this table relate to other existing tables in the system?

Normalization:

• What normal form is our design in?
• Can we improve it?

This page in Phillip Greenspun's online book, explains his own process of modelling his application's database. Excellent page with a lot of learnings.