Paints in powdered form require the addition of a liquid to prepare them for use. The manufacturer's directions as to the amount of oil, varnish, water, or other vehicle required should be followed.
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.
Remove side view mirrors (unless they're to be body color) as well as exterior door handles and locks. This will take some extra time because you need to remove the interior door panels to get these off, but it's worth it. Head lights, tail lights, marker lights and license plates should come off too, but you'll need them in place to drive to the paint shop. So bring some tools so you can quickly take these off once you arrive. Depending on the year Mustang you can just take off the chrome bezels or rings. The shop can then easily mask the headlight or tail light itself and still get plenty of paint around the edges.
There is still no standard labelling scheme for paint. The blue globe label, pioneered by B&Q, led to VOC reduction on the mass market and has been adopted by other brands, while the European Ecolabel, recognised in 15 EU member states, looks like a flower and appears on brands such as Earthborn. Germany also has a Blue Angel label and there is a green Nordic Swan as well. You will find more detailed information on most of the paint company's websites, as well as a wealth of practical and design advice.
Always use a sanding block for flat surfaces. Just your hand behind a thin piece of sand paper can leave grooves and low spots. It's also easier on your hands. For inside curves try wrapping the sand paper around a short section of garden or heater hose. This will help approximate the concave curve and help stay away from sanding through hard edges. On hard edges, like the top ridge of a fender or leading edge of a hood, you need to do this by hand. A sanding block will quickly dig right through the paint on a hard edge and take you down to bare metal. This means primer and more sanding.
For localities where such conditions exist, self-cleaning paints should be selected. These paints are usually so designated on the label. Concrete, plaster, and metal surfaces each present special problems in painting. For instance, paint for use on masonry or new plaster must be resistant to dampness and alkalies, and paints used on steel must have rust-inhibitive properties.
Spend some time talking to the shop manager. He should have the time to thoroughly go over your options and explain their service and pricing. Be clear on what they're doing exactly. Will they scuff your existing paint? Will they be spraying primer? Are they OK painting any loose parts like bumper-ettes? If you're changing colors be sure to discuss the door jambs, trunk area and underside of the hood. Also, get instructions from the shop in writing for proper care of your fresh paint. It will include the number of paint curing days before you can wash it, wax it or let it sit out in the weather.