Before you start importing files into your new repository you should think about how you want the repository to be laid out. It's possible to use any layout but as a basic starting point we recommend a tree similar to this:

Repository Top
|
|- project1
| |
| |- subdirs, files, etc
|
|- project2
|
|- subdirs, files, etc

This layout would allow you to assign individual access controls to each project using your .svn-access file.

The recommended practice is to divide each project directory into a set of standard sub-trees - BRANCHES, TAGS and TRUNK. This allow branching of project revisions and helps to identify releases and milestones in a projects lifetime. This section of the Subversion book covers this type of layout in detail.