One for the students! If you own your own HD system then you should definitely take the time to learn the HD-only automation features it offers. I have however met many students who are intimidated by automation and the most common issue is that rebalancing the track is more difficult once Pro Tools has taken control of the faders. If however you are working on an HD rig you can automate and keep control of your faders using Trim Read.
Although Trim Automation is extremely powerful, the easiest way to incorporate it into your mix is to automate levels using conventional track automation and as soon as you feel that you need to adjust relative levels between you automated tracks, drop into Trim Read.
If you have no automation written in Trim mode (i.e. one breakpoint at time zero and no others) then your fader is free floating and can be set anywhere. Use the conventional automation for track automation and get a free set of faders on top to adjust levels. Don't worry about consolidating trim automation til you're ready, and gold Trim faders are cool!