Counter Strike Source - tips for beginners

This some tips to defeat those high levels

Fake Reload
Shoot a round out of your pistol at the beginning of the match. When you think (or hear) an enemy nearby, switch to your pistol, press reload, and quickly switch back to your main rifle. Most enemies will jump out and attack when they hear the reload sound, because they think you are defenseless.

Strafe-shooting
This has become a staple of counter-strike over the past years, but some players do not quite understand it. If you are in a firefight at range, you can strafe-shoot to maintain accuracy but still make yourself a difficult target.
The way strafe-shooting is done is by pressing (or tapping) the strafe key to get your player moving and releasing it just as you begin to fire. Your player will continue to move for another step, but your shots will be accurate.

The AWP No-Scope
Many people have had problems with this, and it is really so simple. A No-Scope shot is when you shoot an opponent with a sniper rifle without using the scope. For all sniper rifles, the cross-hairs have been removed when you are not using the scope, and the weapons are incredibly inaccurate. This was done intentionally to force people to use the scopes on sniper rifles. The problem with the scope is that it is difficult to make short-range shots, and your player moves very slowly while looking through it, so you become an easy target. The solution to this is the No-Scope shot.
The No-Scope is done simply by pressing the right and left mouse buttons at the same time while your intended target is as close to the center of your aiming point as possible (you have to estimate this). The scope will pop up for a small fraction of a second, and your shot will be accurate.

Cornering
You will notice after playing Counter-Strike for a long time that most players follow very predictable patterns. Ammunition is expendable, and any of the rifles (AK-47, M4, etc.) will penetrate through about the first 3 inches of a corner. When approaching corners that likely have opponents on the other side, shoot the corner. You will often hit your enemies before they see you...

Well, at least this can make you difficult to defeated