Tyranid Infestation Marker:

 To start with, I gave 'em a wash over everything with my "bone wash" (Thanks to Jen Haley's website!) of 3:1 GW Bestial Brown/Black thinned with Mix to about 1:10 paint/Mix consistency. This is what I use as a basecoat for bone over white with my Tyranid test stuff thus far. Funny thing about these Infestation Markers, though, is that I had to apply the wash and then hold 'em upside down carefully tilting them side-to-side whilst blowing on 'em. The depressions between the plates and the tentacles and such really aren't well defined, and with my wash being fairly thin it all flowed down with gravity and pooled on the bottlecap I use as a painting base - thus the upside-down action.

 I started painting the bone areas next, beginning with a coat of 2:1 Vallejo Game Color Bonewhite/GW Brown Ink at a 1:1 paint/Mix consistency, making sure to leave the dark bone color in the deepest depressions. I also touched up the teeth with the same shade.

 Next, I added another drop of VGC Bonewhite, and holding the little guy upside-down again, I brushed the paint on very shallowly from the bottom of the bone plates towards the very top edge. For ease of reference, I started with the tallest "mouth" column and worked around down to the shortest "mouth" column. Following this, I went around the upper rim of the plate edges and, being careful to not mess with the dark brown in the depressions between plates, painted the top faces. I also made sure to touch up the teeth with the same shade.

 Last step on the bone, I took pure VGC Bonewhite at 1:4 paint/Mix consistency, and brushing carefully on a diagonal, I worked up the bone highlighting color from about 3/4 down on each bone plate up to almost opaque Bonewhite on the extreme upper edges of the bone plates and teeth.

 Here is the start of the fleshy areas - I essentially overpainted the previously washed and non-bone areas with 2:1 GW Dwarf Flesh/Brown Ink at 1:1 paint/Mix consistency. Made sure to tidy up in the areas next to the bone, and likewise in the depressions where the original wash might not have covered so well as it should. The color I'm overpainting is a nice darkish browny flesh shade, and will (hopefully) serve as a good base for everything coming after. The nice thing about using slightly thinned paints over the top of semi-shaded previous colors is that the undercolors show through and the overpainted colors add to that effect while evening things out.

 At this stage, I've painted 1:4 GW Dwarf Flesh/Mix on most of the previously painted fleshy stuff. Holding the Infestation Marker so I'm looking down at it, I use a smallish brush (5/0) and starting at the base of where I want the new color, paint towards me so the color finishes up at the highest-most areas. This in effect semi-gradiates the color from least at the base of tentacles and such to most at the top faces. Just to ensure even coverage, I make sure to touch up the upper-most faces with straight painting.

 Final stage of the painting - I painted 2:1 Dwarf Flesh/Elf Flesh at 1:4 paint/Mix concentration on the uppermost raised fleshy areas. Deciding that the teeth didn't stand out nearly so much as I would like (keep in mind that at this point they're the same highlighted bone color as the rest of the body,) I touched 'em up with 2:1 VGC Bonewhite/VMC White layered on at 1:4 paint/Mix consistency.

 For the teeth, I painted from the innermost parts outwards (maw to top of teeth, in other words) so that the thickest area of the lighter bone color would be at the highest, outermost part of the teeth. For the sake of not making too many steps here, I added in another drop of VMC White and carefully applied this to the most highest, most outermost parts of the teeth.

 Finally, for neatness' sake and wanting to darken the "mouths" a shade, I thinned GW Scorched Brown down to 1:6 paint/Mix, and carefully painted in the hollow of the maws, making sure that the thinned paint also crept up the gaps between all the teeth.