Nope. A small amount of water can help dilute a thick vg based
juice, but it will not make more vapor. Vg makes more vapor than pg, so a 100% vg
e-liquid works best for more vapor production.
Vapor production is dependent upon heating
e-liquid on the surface area of a wick/coil setup. More heat may increase more vapor, but at the expense of diminishing returns once your juice starts getting burnt from too much heat. A larger surface area for the wick and coil will allow more vapor - this is one of the reasons that RBAs and RDAs are popular among advanced vapors as they use larger wicks and coils than factory-made devices.