Microsoft article "Designing Your Database Application"

This looks like a great primer on application design, focusing specifically on an Access environment.

Database normalization basics document from Microsoft

Why would I want to use a class object in MS-Access?

Visual Basic Programmer's Guide : Custom Classes and Objects

Classes and objects are a powerful and often underused part of VBA. You will find them featured as topics often on this blog. This link is to a reference on Microsoft.com