A good pair of safety glass with UV protection or sunglasses with side shields will help keep glass dust and repair resins from getting into your eyes. Your shoes should have non skid rubber soles and be comfortable. A base ball type cap is a great way to advertise your business as well as to keep off the sun. Putting your logo on one is inexpensive and can get you noticed. Water is the most important item that you can carry.
Dehydration can be a big problem in the summer heat.
You should also keep a spray bottle of water with you incase you have resin splatter your eyes or skin. If resin happens to spatter on you or in your eyes, flushing it out with water immediately is very important. Carrying an eyewash kit is a smart idea. Cleaning your hands is also important. Soap and water are the best method but not always practical.