How to change an existing openbox theme?

I will take it for granted that you have installed the theme you want to change.
Go to the folder where it is located for instance usr/share/themes.
Create a folder of the new theme variation and give it the name you want.
For example changing the madbox theme, I created a new folder to MadPablo and copied the content of the Madbox folder to this new folder.
Of course it is easier to work from an existing theme.
Now open in the text editor of choice (I prefer geany) the file themerc, it is located in usr/share/themes/openbox-3/.
If it is not there you can use the whereis command in the terminal: whereis themrc

Now we have to use a good colour tool; gcolor2 is perfect for the job and will appear installed as a plugin in geany. Install in Arch with sudo pacman -S gcolor2

Open the themerc file in geany and open the gcolor2 program and use the eyedropper to choose colours. Use a large resolution image of something you like colour wise (content is unimportant). If you got the colour code copy it and put it in place in the themerc file on the spot you want it to be overwriting the existing colourcode
Make some changes and try to understand the various designations of the diverse window items; for more info http://openbox.org/wiki/Help:Themes
If you have trouble identifying an element in the theme use the colour dropper to determine the existing colour of the element you want to change and use the found colour code by doing find code in geany in the themerc file

Now make some changes and save the themerc you're editing.
Open Openbox Gui Config tool, in terminal obconfig

Now select the theme that you took as starting point and make it active. Look around in your browser, open some windows and apps to get a feel how it will look, but already obconfig will give you a rather good example of how it will look.

If you're done with adaptations you can use the create a theme archive .obt option of obconfig and navigate to usr/share/theme/Newtheme folder and name and save it.
It will be saved in /home/user.


Obtheme

There is a gui app to edit a theme called obtheme; have tried it but didn't find it so nice to work with: http://xyne.archlinux.ca/projects/obtheme#screenshots
This is the Madpablo theme I created

Colours are quite different from the original Madbox theme:olive green and light blue.
The fonts used are bitstream vera sans mono for the conky
Monofur,acitve window title; Sans inactive window header and menu header
Menu item and on screen display Neutra Text Book Alt
Apperance settings: Avenir LT Std 12.

Direct link full res screenshot:http://img375.imageshack.us/img375/7655/2010051612740389671920x.png

1. Downloadlink theme
   
   http://omploader.org/vNGZnZQ.obt