Highlighting isn't something I've bad much experience with - in my previous 28mm gaming days I mainly used drybrushing as my technique of choice. Of course, on 15mm infantry that's not really an option.
Se many months ago I got my friend Paul (of http://napoleonicsinminiature.blogspot.co.uk/ fame) to sit and show me what I should be doing to paint an actual highlight. It always seemed like something of a mystic art to me, something I could never quite get my head around.
My first few attempts, after applying AP Quickshade, saw me go back to the original colour (normally the Vallejo English Uniform 921) and almost repaint the model. I rapidly realised this wasn't what I should be doing - it looked crap and was a waste of time.
After that I learnt to be more sparing with the highlight, getting through the models a lot quicker and not getting pulled into the trap of basically repainting them.
Recently I realised that with the scale of the minis and the distance you view them at on the tabletop allows for the highlights to be a bit bolder. Previously I had felt that the infantry looked a bit dark. This then led me towards using shades that are perhaps a bit lighter than I would have considered before. While the minis look a little odd close up, from tabletop distances they look good.
|Base coat + Dark Tone Quickshade|
|English Uniform (921) 66/33 with Khaki (988) - applied to the non recessed areas of the uniform.|
|Just another version of the above shot.|
|Again, slightly better shot showing the highlights.|
|This is me experimenting with skin highlights - something I'm still not too great with.|
Next up will be the matt varnish, which will remove the shine and add another level or two or protection to the models.