A little trick I discovered is to do a simple paint job (I do green armour, grey trousers, black/brown boots/webbing, blue and gold for the shoulder plates, and I was scared for a while doing flesh, for some reason I could never get flesh to look right, until the foundation flesh paint that is (wonderful stuff)). I use a mix of camo green + chaos black for the weapons, looks like FN (the rifle stock) green. I used a dark wash on any detail (like green+black), and a brownish wash on the skin. I do no highlighting.
I find the Catachan green to be a very thin paint, and would use another in the future. So definitely requires two coats.
Okay, so you are finished, but your paint job looks crisp, undetailed and single toned.
Who can rescue you from this dilema? There is a set of magical products produced by Tamiya (I think at Australian$10 each). Each comes with three colours. THe product is the TAMIYA WEATHERING MASTER. Basically its a waxy clay thing, and you paint it on dry. It gives a waxy feel to your model, which seems to protect it as well. I mainly use the MUD option, but also use the Steel and Blue ones for vehicles and heat effects.
I use a stiffish brush.
In the end it makes your units looks a bit "dusty", it looks like you highlighted it, you can play with the amount you put on, from highlighted to downright dirty.
It takes about 10 seconds a model, a minute for a vehicle. I often do it twice, once, then again another day after you have a good look at your work.
A life saver for someone who gets to paint after 11pm.
Another option is to use a spray paint for your basic colour, worked wonders on my vehicles (Tamiya Nato Black) and Gold for my DH. Spray...a few detail colours...drybrush. ...weathering master.
Hija