A summary of the design process

Although your ultimate design will depend on the complexity of your data, each time you design a database, make sure you do the following:

• Break composite fields down into constituent parts. Example: Name becomes lastname and firstname.
• Create a key field which uniquely identifies each record. You may need to create an ID field (with a lookup table that shows you the values for each ID) or use a composite key.
• Eliminate repeating groups of fields. Example: If your table contains fields Location 1, Location 2, Location 3 containing similar data, it’s a sure warning sign.
• Eliminate record modification problems (such as redundant or inconsistent data) and record deletion and addition problems by ensuring each non-key field depends on the entire key. To do this, create a separate table for any information that is used in multiple records, and then use a key to link these tables to one another.

From Databases from Scratch at GeekGirls.com.