Many competitive or "Classic" servers have sv_airaccelerate set to values that make bhopping nearly impossible, regardless of your config.
Before using a bunny hop configuration file, understand the rules of the environment you are playing in. cs 1.6 bunny cfg
But perfect bunny hopping is physically demanding. It requires frame-perfect timings (often sub-15ms) on your mouse wheel or keyboard input. This is where the comes in. cs 1.6 bunny cfg
This is the eternal debate in CS 1.6.