I would recommend priming with Wraithbone or any other light and slightly warm colour. This will make getting a nice tone to the armour easier.
Basecoat armour with Ushabti Bone .
Either zenethal highlight with thinned Screaming Skull from a downward 45 degree angle or glaze in where the light would hit.
Recess shade with Skeleton Horde thinned with Contrast Medium 1:1. Don't be too neat, the contrast should pull towards the recess and give something like a transition. Now is also a good time to paint the under-suit/tubing by your preferred method.
Recess shade everything again, this time being careful, and using Agrax Earthshade . I used is straight out of the pot, but you could mix in a little contrast if you wanted to make life a little easier.
Add a chunky highlight of Screaming Skull to all edges.
Edge highlight everything again with fine lines of Pallid Wych Flesh .
Selectively edge highlight the most exposed curved edges and corners where highlights meet with a pure white of your choice, like White Scar .
Optional: Battle Damage
Add small patches of Mournfang Brown using dots with a fine brush. Try to stick to edges and corners where damage would occur, mostly towards the front of the Space Marine.
Underline the damage from the last step with fine lines of Pallid Wych Flesh .
Dark Grey Undersuit
Basecoat with Dawnstone .
Wash with Nuln Oil .
Highlight most of the ribbing with Administratum Grey .
Selectively highlight with small amoungt of 1:1 Administratum Grey and White .
Silver Chest Device
Basecoat with Steel .
Washe recesses casefully with Nuln Oil .
Edge highlight with Silver .
Selectively highlight with Silver RLM01 Metallic .
Red Eye Lenses
Basecoat with Khorne Red .
Highlight with Mephiston Red .
Paint the two thirds of the the previous highlight closer to the nose with Evil Sunz Scarlet
Paint the third closest to the nose with Wild Rider Red .
Add a dot highlight of Lugganath Orange , right next to the nose.
Add a dot of White Scar to the corner furthest away from the last highlight.
Red Sergeant Helmet
Basecoat with Mephiston Red .
Recess shade with a mix of Mephiston Red and Abaddon Black .
Chunky highlight with Evil Sunz Scarlet .
Fine edge highlights of 1:1 Evil Sunz Scarlet and Tau Light Ochre .
Selectively highlight with Tau Light Ochre .
Mix a little :white into you Tau Light Ochre and add specular highlights to points.
Green Eye Lenses
Basecoat with Caliban Green .
Highlight with Warpstone Glow .
Selectively highlight with Moot Green towards the nose.
Place a dot of 1:1 Moot Green and Ice Yellow next to the nose.
Add a small specular highlight of :white on the exact opposite side.
Crux Terminatus
Basecoat with Dawnstone .
Soft Shade with a mix of Dawnstone and Rhinox Hide . Thin it with at least the same amoundt of Lahmian Medium , to make the shading as easy as possible.
In areas that need extra definition, mix Rhinox Hide and Abaddon Black 1:1 and selectively shade.
Start to highlight ridges with glazes of Administratum Grey .
Add some White to your Administratum Grey and apply thin edge highlights.
Finish with a few small dots of pure White where needed.
Red Gems
Basecoat with Mephiston Red .
Edge highlight with Troll Slayer Orange .
Mix some Dorn Yellow into your Troll Slayer Orange and selectively edge highlight towards the point.
Finish with a dot of Dorn Yellow on the point.
Steel
Basecoat with Leadbelcher .
Wash with Nuln Oil .
Edge highlight with Ironbreaker .
Add fine highlights with small amounts of Vallejo Model Air Silver RLM01 Metallic .
Black Weapon Casing
Basecoat with Abaddon Black .
Edge highlight everything with a thick line of Dark Reaper .
Highlight everything again, this time with a thin line of Thunderhawk Blue . This colour is a good place to put in some scratches too.
With Fenrisian Grey , selectively highlight upward facing edges, corners and prominent edges. Stick primarily to edges where the light would hit and always drag your brush towards the brightest point. If you added scratches previously, reinforce them with a smaller, thinner line underneath.
Finally, edge add small highlights to the centre of the previous highlights and corners with Blue Horror . Try to make them very small, dots if at all possible.
Gold Details
Basecoat with a 1:1 mix of Retributor Armour and Liberator Gold .
Glaze shading in, using Gore-grunta Fur .
If you need to darken the shading, mix some Rhinox Hide into it and do another (more selective) pass.
Highlight raised details with Liberator Gold .
Finish with selective highlights of Silver RLM01 Metallic .
Parchment and Text
Basecoat the paper with Rakarth Flesh .
Wash with Agrax Earthshade . Try not to let is pool in unsightly places.
Reestablish the Rakarth Flesh in places where light would hit.
Add a chunky highlights with Rakarth Flesh and Pallid Wych Flesh mixed 1:1.
Add fine highlights of pure Pallid Wych Flesh .Add some white to the previous mix and pop spot highlights this on corners/points.
For the text, mix Abaddon Black and Rhinox Hide 1:1 then paint in the text with a very fine brush. I find the best way is to randomly paint in dots and dashes in lines, moving my hand along slowly. Do a secondarky pass refining for the best results.
Red Wax
Basecoat with Khorne Red .
Paint everything but recesses with Mephiston Red .
Paint two thirds of the raised areas with Evil Sunz Scarlet .
Cover an even smaller area with Wild Rider Red .
Add specular highlights of Lugganath Orange to corners and strategically within the last highlight.
Purple Wax
Basecoat with Screamer Pink .
Wash detail with Nuln Oil .
Highlight raised details with Pink Horror . Highlight using dots and dabs to make it look irregular and let the colours below show.
With a 1:1 mix of Screamer Pink and Ushabti Bone , add smaller highlights, covering even less area.
If you are feeling brave, add small specular highlight of pure Ushabti Bone within the previous highlights.
Green Wax
Basecoat with Caliban Green .
Highlight raised details with Warpstone Glow . Highlight using dots and dabs to make it look irregular and let the colours below show.
With a 1:1 mix of Warpstone Glow and Ushabti Bone , add smaller highlights, covering even less area.
If you are feeling brave, add small specular highlight of pure Ushabti Bone within the previous highlights.
Hazard Stripes
Basecoat with Averland Sunset .
Wash with Iyanden Yellow .
Carfully paint in the Black stripes.
Highlight the yellow with Yriel Yellow along the top and exposed edges.
Selectively highlight with 1:1 Yriel Yellow and Screaming Skull , within the last stage.
Finish with a small dot of Screaming Skull , within the last stage.
Highlight the black stripes with Eshin Grey along the top and exposed edges.
Selectively highlight with Dawnstone within the last stage.
Finish with a small dot of Administratum Grey , within the last stage.
Yellow Lamp
Basecoat with Averland Sunset .
Cover the area with Iyanden Yellow , pulling pigment away from the source of light, where possible.
Highlight with Yriel Yellow towards the bulb, covering about two thirds of the lamp.
Now start adding White to your Yriel Yellow and gradually highlight towards the centre. By the time you reach the centre, where the bulb would be brightest, aim to be adding a small highlight of pure White .