Nice work... since you asked for a suggestion about Highlighting... I would start with the following... get a drybrushing brush and drybrush over the armour in white... similar to this... Sorry for the crappy pic, but this was from before I had the new camera.... regardless, I think it does a good job picking out the highlights knee and the arms...
You want to go VERY light on the paint and just enough to give a bit of light contrast on the armor bits....
Also, for the heads, try this... Tallarn flesh for a base, wash with Ogryn Flesh, then a light drybursh with Elf flesh to highlight....

You want to go VERY light on the paint and just enough to give a bit of light contrast on the armor bits....
Also, for the heads, try this... Tallarn flesh for a base, wash with Ogryn Flesh, then a light drybursh with Elf flesh to highlight....