a van is a must people don't want to see you arrive in some old hatchback.
even when your sitting in traffic your out to advertise your company.
i run renault trafics and they are still to small for carrying plumbing, drainage tools. let alone parts etc.
you can get away with carrying alot of spares, but i sub contract to call centres at night and you have to carry 80% of general spares.
as for advertising can be £500 + just for a basic ad in the yellow pages let alone business cards, stationary etc.
john as you say dealing with customers and being able to communicate with them helps alot, keeping them informed on how the jobs going or not going all helps.
if you've done a course yes i would work with them if they where prepaired to listern & learn and not a know it all.
if they wanna learn, reliable, respect customers property, ask when your not sure on something etc.