This is going to be a long write up once it is done with a bunch of videos and instructions as in-depth as I can possibly make it, about how to master Cod4. Now to the basics:

1. FPS
FPS stands for Frames Per Second. The higher your fps the smoother everything will be. Well only if you have it set to a number divisible by 1000. For ex. 125, 250, and 333 are the main ones that are the most useful. To make your fps one of these numbers you should first of all type the following commands into your console which is opened by hitting the ~ or tilde key.

/com_maxfps 1000
/cg_drawfps 1

Now look at how high it goes, if it doesn't go above 333 set the /com_maxfps to 250. If it reaches but doesn't stay steady set it to 125. Having an FPS that isn't steady is as bad as having just 80 fps.
If you want to be able to reach a higher FPS you can configure your settings to create your own CFG or you can download someone elses. One that is really popular is yitch3 which I will give you a link right here:
http://configs.eu/_callofduty4/configdo ... yitch3.cfg
If you would decide to create your own CFG make sure you don't go too crazy since some commands can increase ping and remove cool tricks that I will get to later.
But why other than smoothness could you benefit from a higher FPS? Well you run faster, jump higher, shoot faster, and make less sound. You just move faster in general which is really important when playing against other pros.

Commands that can increase your fps:

/r_drawdecals 0
Removes trash laying around on the ground.

/maxpackets 100
Can increase hit registration.

/snaps 30
Same as above.

/r_drawsun 0
Disables the sun.

/cg_brass 0
Turns off shell ejection.

/r_zfeather 0
Softens smoke edges.

/sm_enable 0
Turns off unique Shadows ingame.

/r_multigpu 1
can add more FPS.

/r_cachemodellighting 1
can add more FPS.

/r_cacheSmodellighting 1
can add more FPS.

/r_aaAlpha 0
remove the anti-aliasing / smudge effects.

/r_texfiltermipmode 2
Turns it to bilinear filtering.

/r_rendererPreference 0
Shader Model 2.0 instead of 3.0.

2. FOV
FOV, or Field of View, is the amount of what you can see around you when looking straight forward. Basically it increases your peripheral vision. To change FOV, simply type /cg_fov 80 into the console.

3. Sound
If you ever think someone is hacking make sure they don't use sound, since sound is pretty much a wallhack when used properly. Getting a good headset is essential when you want to become a Cod4 master. Personally I use a Steelseries Siberia v1 and it works perfectly. Also be sure that you turn up your volume or the headset is pretty much useless.
Something else you should not is the amount of sound YOU make when moving around. Now dead silence helps a lot but it doesn't completely hide your sounds. You still make sound when falling, switching weapons, reloading, and using any kind of equipment. crouching around and ADS removes the sound still made when walking since dead silence doesn't completely remove all sound. Being able to move silently is essential in clutch situations.

4. Wall running
There are several glitches in the Quake engine and one of them is wall running. So when you want to get somewhere fast try running while touching a wall. This actually makes you go faster. Wall running greatly helps you get to places faster.

5. Strafing
Strafing is another glitch in the Quake engine which allows you to jump further. To perform a strafe jump you simply turn approx. 90 degrees from where you want to jump to and then while holding both either W and A or W and D you move your mouse as smoothly as you can towards where you want to jump. Strafing is used a lot wether it be in rushes or when trying to reach a vantage point.

6. Bouncing
Bouncing is another glitch in the Quake engine which allows you to jump at an edge at a certain angle and the fly up higher than you were before. Bouncing helps you reach vantage points as well as it can be used to gain speed when rushing.

7. Elevators
Elevating is another glitch in the Quake engine that occurs when hitting an edge at the exact point in the middle. This let's you fly up until you reach the top of whatever you wanted to go up on. Elevating is a bit more complex than bouncing, strafing, and wall running since there are so many different kinds of elevators. I will get more into it later.

8. Dead areas
A dead spot or a silent spot is a spot where if you run on it you make no sound and if you land on it you take no damage. Knowing there spots is extremely helpful since it can help you escape the gunfire, sneak up on your enemies, or rush to certain areas faster without being noticed.

9. Leaning
You can bind a key to leaning left or right in the controls->movement options of the game.
This will make it so much safer and easier to peak from behind walls, it also makes you able to look through holes/spots you wouldn't be able to look through without leaning because leaning gets you lower to the ground.
It also makes you able to look through certain buildings by leaning into them.

10. Sprint reset
When you take fall damage your sprint resets and you can sprint for a longer time. If used properly you can double your sprint time.

11. Prenades
Prenades are preset spots where you throw a nade from and it will land in a specific area where somebody could be. For ex. a prenade on broadcast where you throw a nade down the corridor and get a couple kills.

12. Spawn sniper spots
There are spots that you can go to just outside of your spawn where if you have a sniper you can cover an area where the enemy team could rush. This is a really useful way of getting easy kills since there is almost always someone who is going to one of those routes.

Note that I will be editing this topic later and adding screenshots and videos to show you more in-depth of how to do these certain things.

BB now!
//Relax<3 :]