The goal is to keep the dust down without making mud. Mud will usually **** people off as much as dust will. Remember shaded areas will not dry as fast as ones in the shade. Learn how to adjust each of your sprayers, where they overlap gives twice as much water as when they don't (you can make mud very easy where they overlap). Turn off your sprayers BEFORE you stop moving and turn them back on AFTER you start moving. Puddled water is a big no no. Puddles will result in potholes and that usually pisses off drivers more than dust. As stated above, do not spray passing equipment, you area a support vehical, so don't get in the way or go against traffic. Be deliberate with your route and actions. Everyone else will probably have a predictable haul route which is important to safety and production and everyone knows where everyone else is going. Water trucks that just wonder around and act unpredictably can be very dangerous. Be careful on hills and slopes not to over water and cause erosion or slippery conditions. BE PATIENT. Your job is to keep the dust down. If everything is wet and your tank is full and you are looking for something to do, just watch whats going on. Some of the best water truck drivers know how to just sit and wait (as apposed to over watering). Sometimes there is an art to looking busy when you are actually doing nothing.
When i am running a water truck, i like to spray heavy and drive fast. Some good tricks are to give everything a good layer of water at quitting time, it can soak into the ground overnight and help in the morning. if you can get a chance to start early, give things a good wet coat in the mornings before things are running. Pay attention where machines are loading and dumping. If you are working around highway trucks, often times the engine fan will come on when they are backing up and cause huge clouds of dust while loading or doing slow maneuvering. If there is a mechanic working, they usually don't like water, they would rather lay in dust than mud, Ask them. If there are trucks entering and leaving the site, be mindful that dirt/mud sticking to the tires and getting out onto the roadway is a big deal these days. If they are carrying mud out onto the road, you might want to not water around the exit.
Most importantly, remember everyone will never be happy with the job you do, and rarely will anyone thank you.