Here are some 6mm trenches I've been working on

http://pushingtinwargames.blogspot.co.uk/2015/10/digging-in.html

Excellent PT, I love how you made the trenches below ground level. I've seen too many model trenches that are entirely above ground level. 

That's pretty damn good

That tutorial and the finished product are quite inspirational.  I heartily agree with jbmudshark, the above ground trench systems just kill the period look for me.  They resemble 40K more than Flanders' fields.

Splendid work there.

Though bear in mind that the 'trenches' in Flanders fields were almost all above ground ;-) The watertable was so high that it was not possible to dig more than a few inches down, so breastworks were created from sandbags, etc in order to form parapets and parados.

Robert

Thanks for the complements everyone. TI think it shows up another advantage of 6mm, as I can't imagine it would be so easy to get the same effect with larger figures. If anyone fancies having a go themselves I have now put up the templates online here http://pushingtinwargames.blogspot.co.uk/p/ww1-trench-patterns.html 

I've had a go at this myself, and some barbed wire as well.

This is a complete trench system with barbed wire for The Great war Spearhead.

http://randombitzontheside.blogspot.com/2015/11/digging-in-6mm-trenchs-and-barbed-wire.html