I find the metallic sprays from GW tend to be a little on the transparent side, so an initial undercoat of black helps.

1. Prime with Chaos Black
2. Prime over that with Leadbelcher

Silver (Armour Panels)

1. Drybrush over with Leadbelcher to even coverage
2. Shade the recesses with Nuln Oil
3. Highlight the edges with Stormhost Silver

Gold (Armour Trim)

1. Base with Retributor Armour
2. Shade over with Agrax Earthshade
3. Highlight the edges with Stormhost Silver

Blue (Pauldrons and Cloth)

1. Base with Sotek Green
2. Shade the recesses with Nuln Oil
3. Highlight the edges with Temple Guard Blue
4. Fine highlight with Baharroth Blue
5. Highlight points with Baharroth Blue mixed 1:1 with White Scar :

Black (Ribbing and Details)

1. Base with Abaddon Black
2. Highlight the edges with Eshin Grey
3. Fine highlight on points with Administratum Grey

Green (Eyes)

1. Base with Warpstone Glow
2. Shade the recesses with Nuln Oil
3. Layer the middle with Warpstone Glow
4. Highlight the middle with Moot Green
5. Fine highlight of Moot Green mixed 1:1 with White Scar in the middle

Red (Details)

1. Base with Mephiston Red
2. Shade the recesses with Agrax Earthshade
3. Layer the middle with Wild Rider Red
4. Fine highlight of Fire Dragon Bright in the middle

Grey (Details)

1. Base with Mechanicus Standard Grey
2. Shade the recesses with Nuln Oil
3. Highlight the edges with Administratum Grey

Brown (Leather)

1. Base with Rhinox Hide
2. Shade the recesses with Agrax Earthshade

When highlighting the leather pouches, allow for some edge variation to give the appearance of a worn edge.

1. Highlight the edges with Skrag Brown
2. Fine highlight of Ushabti Bone allowing the previous layer to be seen

Horns

1. Base with Rakarth Flesh
2. Layer the upper one-half with Skrag Brown
3. Shade over with Agrax Earthshade
4. Highlight with Ushabti Bone