NEVER mix more than ONE DENIM TONE in a outfit
If you have a dark coloured jeans, and for some reason you just HAVE TO put on a denim jacket, make sure they're of the same colour tone.
For a super quick example (quick image search from google):
The wrong way
Pieces that are mainly made by denim fabrics are usually big & chunky. So with a tricky colour like blue, it's either 1-tone throughout or a mix with other fabrics(which is what we're usually doing NOW).