Good quality acrylic paints are ideal for painting murals. Also good to use are silicate paints. Regardless of your choice, the pigments should have high stability to light. This becomes extremely important if the mural is likely to be exposed to sun or harsh weather.
A paint that doesn't reflect light is best for a mural. Look for eggshell or matte finish paints. If the cost of using high-quality paints for the whole mural exceeds your budget, then try ordinary wall paint for the under layers or the larger areas; the better quality paint can then be used for any detailing.