How do I apply changes to a theme?

I an new to nopCommerce and so far I'm really impressed.  I'm to the point where I have created a new style for the site and I'm having issues making the changes stick.  I have created my own theme by copying the default one.  I thne went to the .css file and made some changes and saved them but the changes are not applying.  I copied the theme and applied that and my changes were there.  It appears there is some sort of caching taking place.  Is there somewhere that I need to go to apply my changes besides saving the .css file?  Any help would be much appreciated

Thanks in Advance!

Did you create another theme (another directory in APP_THEMES) or just modifoed orangeDark?
If you created your own you should change the default theme to yours in the admin panel

LevGe wrote:

I created a new folder in APP_THEMES and made a few changes and applied it under Configuration > SEO/Display.  The initial changes I made were applied but any subsequent changes I have made since then are not "sticking".

SOLUTION:::  I changed IIS to immediately expire content on the APP_THEMES folder and my changes started showing up as soon as I made them.  

NOTE: If you do this you will probably want to turn it back off once your changes are made.  That way you can take advantage of browser caching.

I don't know if you tried it but ctrl+f5 in most browsers will give you the most updated version of the site.