I'll go through step by step and have taken the assumption your miniature is already undercoated (I used white - namely the Army Painter white Undercoat Spray). I also used the following Citadel paints/shades:
- Averland Sunset (Base)
- Seraphim Sepia (Shade)
- Usahbti Bone (Layer)
- White Scar (Layer)
1: Base Coat the bone area of the miniature
Go ahead and apply a base coast to the bone areas with Averland Sunset. Be sure to water it down and build it up rather than just apply straight from the pot. Be sure you cover all the bone areas and allow the paint to fully dry before moving on.
2. Apply the shade to the model
You now want to to apply Seraphim Sepia to the miniature - be especially sure to make sure you fill all the nooks and crannies (i.e. eye sockets, ribs etc). You will already notice significant detail coming out already here!. This step is crucial - miss it, and you miss a huge part of the detail that will come out later! Shades take a little longer to dry, but it is important the shade is fully dry before moving on.
3. Dry brushing the Ushabti Bone Layers
In this step, we will dry brush layers of Ushabti Bone and White Scar to the bone areas. This is good as it will generally mean you do not paint over the nice shades and begin to really bring out the bone too. Firstly, dry brush the Ushabti Bone to the miniature. Again, do this in stages and build it up gently. Do not worry about neatness either - dry brushing is a messy affair anyway.
4. Dry brushing the White Scar Layers
Dry brush the White Scar. This is much like the Ushabti Bone step, but you will most likely want much less coverage otherwise there is a danger you will paint over the miniature with too much white. Note: This is the individual bit, you might want whiter bone or "dirtier" bone. If you fluff up, not to worry - just apply some Seraphin Sepia and resume. Just repeat steps 3 and 4 as necessary for your requirements. The result for me was a somewhite white bone, but also "dirty" in places thanks to the shade. For me, the white brings it out further.
5. Paint the Rest!
With the messy dry brushing done, all that's left is to carefully paint the details and base the miniature! I hope this has been helpful to you.