If you want to use touch-up paint to repair a scratch/chip it is like everything else anymore, Best left to a professional. You have to clean/prep the area with prep-solv or in a pinch, rubbing alcohol. Then tape all around the area to be repaired and lighly sand the chip/scratch. You are not going to metal just enough to give the paint something go bite. I use 1500 or 2000 paper wet. Then apply several VERY light coats of paint to only fill the scratch. Try to not let the paint on the repair become thicker than the surrounding area. This requires a VERY light touch as you may have two colors and a clear, so each coat needs to be paper thin. If the repair does end up to "deep" you can level it with a rubber wet-sand pad and some light paper, just take your time. NEVER use your finger, you will cut a finger shaped groove.
Let it dry competely between coats and then overnight after completion. Next day tape around the repair area and sand with 2000 or 2500 wet, gradually pulling back the tape until you have about a quarter sized area sanded. Then buff with a agressive foam pad using light compound until sanding scratches just start to disappear, change to medium pad and use ( I use Mothers #1 here) and finally use a non-aggressive pad with you favorite swirl mark remover (I use Mothers #2) here. The repair at this point should have no noticeable appearance. Couple days later use you favorite wax.
Been doing this type repair for 35 years with excellent results but without fail everyone I have done it for expects it to take 5-10 minutes and look just like it never happened, you can do a 10 minute touch-up but it will look "touched up", not repaired.
IMHO.