I have noticed that my particular instance of Trac is not running quickly and has big lags.  This is at the very onset of a project, so not much is in Trac (except for plugins and code loaded into SVN).
Setup Info: This is via a SELinux system hosted by WebFaction.  It is behind Apache, and connections are over SSL.  Currently the .htpasswd file is what I use to control access.
Are there any recommend ways to improve the performance of Trac?
It's hard to say without knowing more about your setup, but one easy win is to make sure that Trac is running in something like mod_python, which keeps the Python runtime in memory. Otherwise, every HTTP request will cause Python to run, import all the modules, and then finally handle the request. Using mod_python (or FastCGI, whichever you prefer) will eliminate that loading and skip straight to the good stuff.
Also, as your Trac database grows and you get more people using the site, you'll probably outgrow the default SQLite database. At that point, you should think about migrating the database to PostgreSQL or MySQL, because they'll be able to handle concurrent requests much faster.
How to improve Trac's performance