It doesn't take much to make your army look good. It's as simple as a wash and a highlight in most cases. Occasionally, I'll do things for people to help them improve their armies. In this case, I got the job of painting shoulderpad icons on a squad of 20 Imperial Guard.
The troops came to me with just their base colors on (read: completely painted). While painting icons on shoulderpads, I decided to help my fellow Old Timer out and I added two more painting steps to his models to show him just how easy it is for one and how quickly it makes your models go from just painted to really looking like completed models. Now, we have that kind of relationship where I can do this to his models... it's not something I do to everyone's models I get.
I've done this once before with a Lord of the Rings model for another person to show him how it easy it was to get from base colors to finished model with just one wash and single highlight.
I didn't do anything to the models other than to add paint. I didn't clean anything up, repaint anything or do any touch ups. I simply added a wash (different colors for different areas) and then a single line highlight after that.
Starting with 20 Guardsmen who came to me with their base colors already applied, it took me an afternoon (about 4 hours) to get them "finished." Now they still need to be based, but we all know how incredibly easy that is to do.
The point of this whole thing is this, it doesn't take all kinds of fancy, intricate, involved techniques to make models look good. It really comes down to a wash and a highlight. By just adding those two things, you can improve a model's appearance dramatically.