1) Basecoat: 2:2:1 Mechrite Red : Blood Red : Dark Flesh
2) Lining in: 2:1:1 Blood Red : Dark Flesh : Black
(all of the shadows and panel lines on a normal figure skip for tanks)
3) First Highlight: 2:1 Blood Red : Dark Flesh
4) Second Highlight: Blood Red
5) Coarse Edge Highlight: Blazing Orange
6) Edge Highlight: 2:1 Blazing Orange : Vomit Brown
7) Wash: Baal Red
(for tanks make it a thin filter of Baal Red avoiding any pooling)
8) Final Edge Highlight: 2:1 Blazing Orange : Vomit Brown
(around helmets and other prominant locations).
Obviously for tanks and similar you ignore stage 2 and use progressively lighter drybrushing to achieve stages 3-6. Ignore stage 8 as it will achieve precious little.
The "heavy" look on the tracks and exhausts is achieved using something that is still called "Jeff Rust" in the GW Stores that I taught it in. Essentially it is a progressive stippled highlight that follows this pattern:
1) Basecoat: Dark Flesh
2) Heavy Stipple: Vermin Brown
3) Stipple: Macharius Solar Orange
4) Drybrush: Boltgun Metal
5) Wash: Badab Black or Devlan Mud
The degree of "rustiness" is controlled by stages 4 and 5. A lighter drybrush of Boltgun Metal will achieve a rustier vehicle (at stage 3 it looks completely rusted). Replacing Black with Brown in the wash stage will also achieve a more ramshackle appearance. Given that this is an Imperial vehicle I made the rust minimal but all those layers add a nice sense of depth and weight.
Anyhow, when transfers arrive I shall apply those and go through the weathering processes that turn it from a toy vehicle into a war-torn weapon of war!