No trick really. I just use it sparingly, and rub very lightly. It removes that nasty looking oxidized appearence if you go slow and careful. Obviously you don't want to do any harm to the bluing, but I believe personally that too many guys think any kind of cleaning outside of Breakfree or Hoppe's etc., will ruin bluing. It is pretty durable stuff if cared for a tiny bit.
The guns from the mid '80's don't have near the polishing to them right from the start that older guns do, and it gets progressively better the farther back you go. I have them ranging from '89 on back to the '50's, and there's a marked difference in appearence of even the same model as you go back into the past. The better the polishing job in the beginning, the better the bluing will look, both new and in the future when being cleaned up.
I have been told not to use Simichrome on nickel, but I have found that if you are careful and don't try to restore the guns appearence in one fell swoop, it works darn good. Flitz works even better. The package that my current tube came in lists Flitz as being suitable for use with blued guns.
One other thing that I find works well when polishing blued guns is to make absolutely certain that any and all surface fouling like that from primers and powder are removed first. They act more like an abrasive than the polish does IMO.
Edited to add-
Even on a really nice polishing job under the bluing, there is a sort of grain to the polish if you look at it under a bright light (halogen works great for spotting defects and the grain in the polsih/metal), or magnification. Try to polish/rub in the same direction as the original. It goes a long way towards making the polsihing job more appealing, and really popping.