This is how I painted the yellow and blue armour of my Craftworld Iyanden Eldar Guardian.

1. Basecoat all of the yellow armour with Averland Sunset .
2. Use Iyanden Yellow diluted with Contrast Medium , mixed 1:2 and go over all of the yellow again.
3. Selectively shade the deepest recesses of the armour with thinned Mournfang Brown .
4. Bring the plates and exposed of the armour back to the base colour by painting/glazing Averland Sunset over them again.
5. Chunky edge highlight of Averland Sunset and Screaming Skull mixed 2:1.
6. Fine edge highlight of Averland Sunset and Screaming Skull mixed 1:1.
7. Selective highlight of pure Screaming Skull . I would advise sticking to corners and the most prominent areas only.
8. Dot highlight of Screaming Skull mixed with a little pure white, like Dead White .
9. If at any point you are dissatisfied with the vibrancy of the yellow, I would recommend adding a little ink (like Vallejo Game Ink Yellow ) into your paint. You can then glaze over the affected area and start building up colours again.
10. Basecoat the helmet and and relevant areas with Macragge Blue .
11. Recess shade any raises detail with Kantor Blue , watered down to a glaze. This may take a couple of attempts. Alternatively, use Drakenhof Nightshade .
12. Chunky edge highlight of Alaitoc Blue .
13. Fine edge highlight of Calgar Blue .
14. With Calgar Blue and Blue Horror mixed 1:1, selectively highlight the most pronounced parts of edges and corners.
15. Place dot highlights of pure Blue Horror in corners and in the centre of the previous steps highlights.