I've been playing with some JWM themes , antiX makes them easy to find and play with.
What I did to try to map out the colors is take an existing theme and rename it , then play with it.
After looking at a few themes , you get how the colors work together , mostly the 2 color gradient stuff.
I found the edge of the active and inactive windows are too skinny to grab with my mouse quickly.
The fonts are pretty basic , you can call out whatever is currently in your system , I like the terminus series myself.
I like to add a "clock" parameter to the theme and adjust its size , it just uses strftime codes for the display.
I like to refer to this site to find the color codes.http://www.colorhexa.com/7aa1d1
Just punch in what the theme shows and you have your color to locate in the theme.
I'm no pro , but I've had some quiet time lately to fiddle with my system.
Here's the clock lines to add to the theme as needed.
Just add it after </TrayStyle>
and before <PagerStyle> in the theme.
This gives a black large lettered clock
This shows how to format the clock
<!-- Additional Clock attributes: format, height, width, zone -->
This line goes in ~/.jwm/tray
I didn't find much either on making your own , but it's not too hard if you like to fiddle.