1. start CoD4 and go to the rankwindow
2. look at the points for the next rank
3. press the right hotkey to get points near the next rank
4. join a server and kill an enemy so you will reach the next level
5. repeat step 1-4
If you rase your point too much and you will need -xxx points to reach the next level, you need to use the -10points hotkey to go back to +xxx points.
great job