I have no idea if this will be of any interest/use to anyone at all, and to top it off, the pics are from my mobile so aren't very good.
Anyway, this is how I have gone about painting up my 15mm ACW confederates.
1. Start off by gluing the models to the base with superglue, once dry pva up the base and add sand, clean the edges before it all dries.
2. Spray them black.
3. Drybrush with grey, (may want to use blue for union) This is just to pick out some of the detail as if you've ever tried painting base colours on a small/busy matt black model, you'll know how hard it is to figure out what is what.
4. Paint on the base colours, start at the bottom of the model and work up, and from the bottom layers up. take your time here, do it in batches when required, all the shoes, all the trousers, jackets before belts etc.
5. The idea is to get the hard to reach areas before you do top layers so that you don't mess up on the outer layers trying to get into a deep area. Remember that the black undercoat can show through in the hard to reach recessed areas, that's fine as it creates a natural shadow anyway.
6. Dry brush the base with some browns to pick out the texture of the sand.
7. Ink it; The obligatory Devlan Mud wash to add shading to the model, this adds depth to the flat base colours and if you're careful in your application, the last bit you'll need to do on the models themselves.
8. Paint the base edge green to match the gaming mat/board/tiles etc. PVA areas of the base around the bigger bits of sand then add a sand/flock/static grass mix. This will leave your base with a mixture of drybrushed brown base material, flock and sand, this takes time to figure out what works and what doesn't look so good to you, chances are you're just being picky.
9. Lastly some of my older painted models, added to a base that was painted brown with green edging and PVA'd up with a mix of flock and sand.
Colours used. Snakebite Leather (Boots, belts and pouches), Calthan Brown (base, guns, beards and hair), Goblin green (base edge), Sobek Green (trousers, it's blue!), Tausept Ochre, (Butternut jackets, hats), Dheneb Stone (Blanket roll, hats), Tallarn Flesh (skin), Astronomican Grey, Adeptus Battlegrey (Hats, a couple of jackets), Mithrill Silver (Bayonets) Chaos Black, Skull white (bits on the officers) The Butternut jackets was something primarily associated with North Carolina regiments as far as I'm aware, I read it in one of those random articles somewhere and it'd been mentioned elsewhere so I figured there must be some truth to it.