Either edge of trim is painted with body color, and is where caulking is applied at most 90 degree angles. Painting trim only, cannot feasibly include caulking, as this fails and opens up over time. Most homes need new caulking when painting the exterior, and a close inspection can determine.
Scuff for paint. Once your Mustang is totally stripped of exterior chrome it's time to scuff up the existing paint. The paint shop should do this also, but on the lower end paint packages they won't spend much time here. It's better for you to do it so you know it's done thoroughly.
STIPPLING. Whether you desire the effect of stippling (tiny paint dots) as a decorative effect, or if you have a wall which has an uneven surface and you feel you can hide the defect by stippling it, you may accomplish this result very simply.
If paints have been allowed to stand and hard lumps or skin have formed, the skin or scum should be removed, after which the paint can be stirred and strained through screen wire or through one or two thicknesses of cheesecloth.
Have plenty of newspaper around. After you clean your brushes wrap them in a plastic bag.
Do all your own body work . As mentioned earlier, the key to keeping your paint shop costs down is to do as much as possible before you take it to the shop. This includes body work, if you've got the skill, or the patience to learn the skill. Bodywork is time consuming. It requires several steps that must be done in the correct order, with the correct curing times in between. Shortcuts here will show up like a sore thumb in your new paint job, so don't be tempted. If you don't have the skill to tackle the body work yourself then it's smarter to let the paint shop do it. Just understand that this raises the cost of your paint job significantly. Good body work takes hours upon hours and having a professional do it can easily exceed the cost of a cheap paint job.
No single product can do all these things. There are several types, all available under a variety of trade names. The trade names are, to put it kindly, confusing. For example, two brands of the new paints use "rubber" in their trade names, yet neither is a rubber-latex paint and each is actually an entirely different type of paint from the other. To get the right paint you have to read the fine print on the label and find out what is actually inside the can.