Wow, great topic for car lovers! My two cents on a number of points raised (I'm a former detail shop owner and detailer)...
First, Griots has some fantastic applicators if you dont want to use the toothpick... part #50406. Work well when you use very little amounts of paint. They also have a nice tool for scraping the wax and crud out of the scratch before applying the paint (mine came with the applicators as a kit).
Second, I like to use a little bit of primer in the scratch. Many, many, many spot repairs come loose due to poor prep (cleaning) and lack of adhesion without primer. Any small quantity of automotive primer will do.
Third, practice on an inconspicuous spot first! Maybe your "significant other" has a car with a scratch or two that can be attacked without dire consequences... or else your winter whip.
Fourth, as mentioned earlier, Always start with the least aggressive approach for your compounds, pads, wetsand paper, etc. You can always get more aggressive when needed. More aggressive usually results in being too hard on the car's finish and that can cost you time, money, or both.
Fifth, when working on plastic with a machine - machines create heat and heat is not plastic's best friend. Keep it moving, don't stay in one spot, use your free hand to feel the surface in case it is getting warm. Paint will come off a hot plastic surface faster than you'll ever believe (especially with a pad moving at 1500-2000rpm)!
I hope that's useful to someone out there!