A few weeks ago I posted a question asking about sanding acrylic enamel.
After following some suggestions I am still having problems.  After the
sanding (600, 1000, and 1500 grit) the paint looks very dull.

Applying rubbing compound does not seem to help much.  Am I applying the
rubbing compound incorrect?  I am applying as if it is wax.  The compound I
am using is Turtle Wax "Rubbing Compound".  Should I try another brand?
More industrial strength compound?  Should I be using a machine to buff the
compound?

What am I doing wrong?

Thanks for your advice!

Paul Borghese