Ok, model is painted and has a clear finsih over the paint. When I apply the wash do I do it to each piece of raised detail or to the entire area. You would not believe how much trouble I have been having with washes.

That really depends on personal preference..I do small areas at a time. Sometimes it can take a few washes to get the look you want. Give each one plenty of time to dry before going to the next one.BTW..I use oils.

I also recommend repeated light coats over areas
you dont want to overdo it, so better to go in slowly with multiple coats
than one "sure to darken down the recesses and corners" and overdo it.

Also I usually put some Future over my model to help the wash run into the panel lines and corners through capillary action (or whatever physical forces are getting the job done)

I think the gloss finish will help it run, preps for decaling, and a shot of dullcote will set things right before considering the model "done."
HTH

In my opinion, overall washes in most cases don't look realistic, vehicle looks like it has been driven through the dirty water or something. You should apply wash that way if you want that dirty look, othewise apply it only to the details, hatches, panel lines, etc.