Wow, That's a tall order!
There's really no major differences in RH's "potential ."
That is, everything that you could see in TrueCode will now be XML
instead of HTML, in addition to using a CSS file for additional
formatting.
The major improvements, as I read on their web site, is in
"process" improvements (MDIs, snippets, variables, improved source
control, etc.). What your WebHelp will look like will be a
combination of your skills in HTML, CSS, and maybe a little
JavaScript.
You'd do well to perform some internal research (user
preferences, company colors and fonts, etc.). Check out
Rick
Stone's web site and
Peter Grainge's web
site for tons of neat tricks and best practices.
Come back when you need help with more specific subjects.
Good luck,
Leon