As far as washing, everyone will have their own way of doing it and stuff that they use. Any good quality auto car wash will do the job, along with a soft head brush on a telescoping pole to get the high spots.
As far as wax, it personal preference. The info on waxing graphics--- (got the info from a vinal/graphic supplier)--- don't use anything with "carnuba" wax or products containing it on the graphics. Its the carnuba that will eventually dull and damage the vinyl graphics. Use a "wax" thats a synthetic. I use Turtle Wax Ice, both the wax/cleaner and detailer, on the entire body, graphics included. Dosen't last as long as real "wax", but is much easier to apply and remove. Leaves no residue and is safe for everything, even plastics, rubber and vinyl tape/graphics.