This is the step by step for one of my custom chapters, the Spectral Claws.
These guys are Raven Guard successors, and lean heavily on forward deployment and ambush tactics.

1. Priming:
   I prime with Matt Black Undercoat followed by a zenithal prime using Mechanicus Standard Grey Citadel black spray would be fine here, but I didn't have it when I started, and stuck to army painter to keep things uniform as I progressed.
2. Armour Plates:
   At this stage, I do the main armour colour all together.
   Drybrush the armour plates and fabric with Mechanicus Standard Grey to catch a few places the zenithal missed. Then an all over shade with Nuln Oil .
   A heavy drybrush with Skavenblight Dinge , then progressively lighter passes with Stormvermin Fur and Karak Stone will block in the main colour. The fabric can be done the same, as any cloth will just get contrast over this sketch later.
3. Undersuit:
   The rubber undersuit joints get a coat of Dawnstone followed by Gryph-charger Grey
4. Cloth and Leather:
   As stated above, the cloth areas get 1 to 2 coats of Militarum Green over the existing drybrush.
   The leather parts get Rhinox Hide for now, returning to these later.
5. Trim:
   The trim gets a coat of Balthasar Gold for now.
6. Metal:
   The metal parts get a coat of Doombull Brown , we're going for a heavily weathered effect here.
   Wash this with Nuln Oil for definition, then an overbrush of Leadbelcher
7. Skin and White Panels:
   The skin and the white armour panels both get 2 thin coats of Rakarth Flesh
8. Wash Steps: Agrax Earthshade goes over the trim, the white panels, the leather, and the undersuit here.
   The armour panels and the metal part both get a recess shade of very watered down Skrag Brown . This doesn't need to be even, it's meant to make them look rusty and battered.
9. Highlights:
   The leather gets a highlight of Baneblade Brown , the metal a highlight of Runefang Steel and the trim gets Runelord Brass at this point, and they're then complete.
10. Skin:
    Returning to the skin, they get a coat of Kislev Flesh followed by a wash of Reikland Fleshshade
11. White Panels:
    The white panels get a coat of Rakarth Flesh , avoiding the recesses we shaded. Then, a coat of Pallid Wych Flesh This is washed with Seraphim Sepia , and then gets another coat of Pallid Wych Flesh followed by Seraphim Sepia into the recesses and lines.
12. Weathering:
    The white panels, and bits of the rest get a sponge of Rhinox Hide . Any larger blotches get a little Leadbelcher in the centre. On the white panels, Seraphim Sepia is applied around the flecks of Rhinox Hide.
    A mix of Blood For The Blood God and Typhus Corrosion is applied to the weapons, simulating dried, oxidised blood. Agrax Earthshade is washed over the legs from the knee down, and then a sponge of AK Interactive Wet Ground over this on the feet adds some more mud.
13. Glow:
    The sights, eye lenses and other glowing parts are based with Pallid Wych Flesh and then given 2 coats of Talassar Blue
14. Basing
    AK Interactive Wet Ground is added to most of the bases, leaving some empty spots for puddles. When this dries a bit, I alternate between Dark Angels Green and Militarum Green to paint in where the puddles will be, then add Army Painter Swamp Tufts, and then AK Interactive Puddles over the green. The rims are painted Abaddon Black