We have had our red xfire for two months and are sick about having to already repair two paint scuffs left from a rock thrown from an oncoming semi

We picked up a tube of the right color from the dealership for the repair-- as a professional artist, I have a steady hand and am used to paints (just not used to painting on cars, i.e. my new red xfire!) So, obviously I want to do this "right". I have been told to just be sure I don't "bubble" the paint. Does anyone else have any advice towards a successful touch-up paint job?

Also, we are considering a bra to avoid this in the future, but would appreciate your opinions on this too. Thanks for your responses!