Quick and bright NMM from french studio Graphigault. I't perfect for Grey Knights. The guide suggests Games Workshop paints, but you can use similar ones from any manufacturer.
Use Administratum Grey for showing the hotspots.
To smothen the shift between The Fang and Administratum Grey you need to mix them together and then add Lahmian Medium 1 to 1. Apply this mixture to the edges between the colours.
Mix pure Ceramite White with Lahmian Medium to draw points and hotspots. You can also mix white with Administratum Grey and highlight all armor edges.
Mix Xereus Purple and Sotek Green with Lahmian Medium 3 to 1 to create shades on the black primer.
Seems hard but you will definitely manage if you try hard enough. Also, a good terrain for such models can be ordered here