Tools, wheels, and tracks:
I paint all of these seperately from the tank itself (unless they are molded to the kit like on the smaller scales).
For the tools, I like to paint the entire tool first with the base
color (using an airbrush). Once the main vehicle is base-coated,
I paint the wood a brown or orange and the metal a mixture of steel and
black.
For the wheels, I paint the whole wheel the base color and then paint the rubber and track wear marks.
The rubber is usually Polly Scale grimy black, and the wear marks are either silver or a mixture of silver and black.
For the tracks, we all have our own way of doing these. Pretty
much, I start with gray or primer gray, brush on multilple coats of a
rust wash or dirt wash (or both...make sure that each is really dry),
and then I dry-brush a mixture of silver and black in the areas prone
to wear. If there are rubber sections, this area gets a coat of
flat black over the primer.
Now you put all of these on the kit (probably using CA glue since
you've got multiple coats of paint on them). Some people do build
the kit first, but I don't have that steady of a paint brush or the
time for vast amounts of masking.
Once the kit it together, it is now time to weather.
Grant