George,
I use primarily Tamiya acrylic paints, with Future (or another acrylic clear coat), and I like to use artist oils thinned with Turpenoid for washes. For most accent work I use a long narrow brush and let the wash "wick" into areas I want to highlight. The oils seem to work better for this than other kinds of paints. For aircraft panel lines, however, I use Paul Boyer's sludge wash (described in a past edition of FSM).
TomB