Base Armor
Base and layers:  Wraithbone    Screaming Skull    Castellan Green    Leadbelcher    Balthasar Gold    Corvus Black    Dryad Bark    Kislev Flesh  
Shades and contrasts:   Agrax Earthshade    Guilliman Flesh    Magos Purple    Contrast Medium    Carroburg Crimson  
Highlights:   Loren Forest    Flayed One Flesh    Sycorax Bronze    Stormhost Silver    Eshin Grey    Gorthor Brown    White  
- Follow Duncan's awesome tutorial (https://www.youtube.com/watch?v=ImGHTaS3wNw) 
 - Additionally wash all white armor with 50%   Seraphim Sepia  and   Contrast Medium  mix to darken it down
 
Daemon shoulder pads
- Base with   Castellan Green   
 - Shade with   Agrax Earthshade  
 - Broad highlight with Loren Forest
 - Closer to face, highlight with   Elysian Green  
 - Point highlight with   Nurgling Green  in center of face 
 
Bile or slime drops
- Base with   Warpstone Glow  
 - Shade with   Coelia Greenshade  
 - Broad highlight with   Moot Green   
 - Highlight points with   Flash Gitz Yellow  
 - Coat with   Ardcoat  
 
Insect eyes
- Layer with   Flash Gitz Yellow  
 - Shade with   Athonian Camoshade  
 - Repeat shade with   Athonian Camoshade  
 
Skulls
- Base with   Zandri Dust  
 - Wash with   Agrax Earthshade  
 - Highlight with   Ushabti Bone  
 - Further highlight facial features with   Screaming Skull  
 
Shrink heads
Based on B&B (https://brushandboltgun.com/2017/10/18/death-guard-painting-techniques-part-2/)
- Base skin with   Rakarth Flesh , wounds with   Mephiston Red , boils with   Averland Sunset  
 - Wash skin and boils with   Seraphim Sepia , wounds with   Carroburg Crimson  
 - Brighten up skin with   Rakarth Flesh  
 - Paint the sewed up pieces   Corvus Black  or   Leadbelcher  
 
Plasma glow
There are two approaches to building a plasma gradient: i) from light to dark and ii) from dark to light. I chose i) as it conveys the idea of the coil cooling the more it is exposed to cold air. For this purpose, we start with a bright yellow close to the casing and center of the coil and work our way to darker colors to the middle/top of the coil.
- Base plasma coil with   Yriel Yellow  
 - Dry brush larger oval area with   Fire Dragon Bright   
 - Dry brush slightly smaller oval area with   Troll Slayer Orange  
 - Over-dry brush with   Troll Slayer Orange  onto the casing for a small OSL effect.
 - Dry brush even smaller oval area with   Mephiston Red  
 
Cloth and capes
- Base with   Screamer Pink  
 - Wash with   Basilicanum Grey  
 - Highlight with   Screamer Pink 
 
Daemon mouths
- Based on a great tutorial from B&B (https://brushandboltgun.com/2017/10/15/death-guard-painting-techniques/)
 - Paint flesh as above with   Kislev Flesh , inside of mouths with   Mephiston Red  
 - Wash flesh with 50%   Guilliman Flesh    Contrast Medium  mix, wash mouth with   Druchii Violet  
 - Layer teeth with   Rakarth Flesh  
 - Wash teeth with   Seraphim Sepia  2x, (one layer all over, the second to darken the base of the tooth)
 - Broad highlight of teeth with   Rakarth Flesh  
 - Treat tongues like tentacles above (see Base Armor) and fade from   Guilliman Flesh  to   Magos Purple  mix to the tip of the tongues. 
 
Fly wings
- Layer with   Lothern Blue   
 - Edge highlight top of wing with   Baharroth Blue  : 
 - Edge highlight bottom of wing with   Teclis Blue  
 
Smoke
- Base with   Celestra Grey , wash with   Nihilakh Oxide  
 - Heavy drybrush with   Ulthuan Grey , then manually strengthen some of the ridges. Highlight sharpest edges and tips with   White 
 
Basing
Marsian/red planet desert builds a good contrast against the models base colors and the brown elements tie the mini together. The steps below are based off of another great tutorial from Duncan (https://www.youtube.com/watch?v=O8hFQjwiUmQ).
- Glue rocks onto base
 - Layer with   Doombull Brown  
 - Thinner initial layer with   Martian Ironearth , then thicker layers where earth needs to break with thickest blobs of paint randomly on the base. Leave out rocks.
 - Wash with   Reikland Fleshshade  
 - Dry brush ground with   Tuskgor Fur  
 - Dry brush rocks and sharp objects with   Karak Stone  
 - Add grass and painted skulls (see above)
 
Horns
- Base with   Zandri Dust  
 - Wash completely with   Seraphim Sepia  
 - Glaze outer 50% with   Agrax Earthshade  
 - Additionally, glaze outer 25% with   Agrax Earthshade  again