Slightly different approaches are required for painting masonry (concrete and bricks), depending on whether it's a horizontal surface such as a path or driveway, or a vertical surface such as a rendered wall. With these tips you can paint with more confidence that it will be right the first time. These surfaces will take a lot of wear, so you should use tough pavement paint, available in fast-drying enamel versions as well as acrylic.
Wash the surface first with a concrete cleaner and a stiff scrubbing brush to remove any grime, dirt and moss; allow the area to dry for at least 24 hours.
Coating concrete or brick with white vinegar is a good trick to help the paint stick and last longer, particularly if it has a smooth surface. The acidic vinegar will slightly etch the surface of the concrete to create a better key for the paint. You can also use a mild hydrochloric acid, following the manufacturer's instructions. Painted concrete floors should almost always be treated if you intend for the painted area to be a high traffic zone.
You don't need a primer, but dilute the first coat by 20 percent to help with the coverage. As concrete usually has a rough surface, you'll need a roller with a longer nap.
When painting a horizontal area with high traffic or a lot of moisture around, be aware that it's likely to become a slip zone. Add a nonslip additive to assist with this problem. Experiment with adding washed sharp sand to the paint; this can be purchased from a hardware store or you can go to a marine supplier or ship chandler to buy commercial nonslip additives, which may be made of crushed walnut shell.