How do I add dimming control to my following LED toggling program on Arduino? Also how do I improve my existing code?
How do you improve your code?

Firstly there is nothing disastrously wrong with you code, it could do with a polish, but who's code couldn't?

In the dim and very distant past I was told "you write code once but read it many times" so try and make your code readable and clear.  


If the values aren't going to change then they should be constants or #defines.
ALWAYS initialise variables.  (Doesn't matter on an Arduino because the compiler does it for you, but its good practice).
Boolean should be true or false.
You are writing C/C++ not Java.  Opening braces { should be on a new line.  It makes the code easier to read and match up the braces.
Unless your space bar is broken, put spaces after commas and either side of equals.
Using function parameters and less global variables will make you code more reusable.  Imagine the day when you start a new project and copy and paste functions from previous projects and finish the code in 15 minutes.
One statement per line.  cwState = wwState = HIGH;.  In this case its not a problem, but you can get into states where side affects screw everything up.  Also its easier to read.
Comment the code as you go, because you'll never go back.  
Explain what each function does, because you'll have forgot by
tomorrow.


I hope that helps you write better code and none of it has caused offence.