Let me remind you that this is not A common multiplayer  first-person shooter(FPS) games like you've been play for years. In those games you can kill your opponents like crazy and if you get killed, you'll respawn back into the action and continue 'fragging'. But in CS, it's not like that simple. If you get fragged, you will not be respawn, but instead you will become a 'ghost' flying around the map to see your other team mates trying to win the game. You cannot communicate with them while you in 'ghost' mode coz what you typed can only be seen by other fellow 'ghosts' as well. So, here's some tips I can give you during my experience playing this great game:

1)Team work is important 

It's obvious that Cs is a multiplayer team game. So, you better team up with your friends to eliminate the other team so that you will have a high chance of winning. Your teammates can watch after you back and that make you a lot safer to proceed without any doubt. IF you are stubborn and thinks you a are master of FPS games, it is  not certain that you will be able to survive by assaulting alone.

2)Strategize your team

Divide your teammates into 2 groups. One is gunner and the other is sniper. Snipers can make an observation via the zoom scope while giving info to the gunners to proceed. This way, your team should win....I think. Careful planning will surely result in victory to your team.

3)Buy the best weapon 

You should buy a weapon that suits you most. You also should know the pros and cons of weapons. Sub-MGs easy to get a headshot but the recoil are worst while shotguns is lethal in close combat and sucks at long range. Rifles have capable of punching power and sniper rifles scores big at long range although the reloading time is a worry. 

4)Aiming is the key

Aiming is very important in CS. You need to master in aiming to successfully frag your opponent. Always remember that headshot is a lethal takedown and firing at the chest maybe not so effective if your opponent wears armor. It is possible to get a headshot with a TMP...for the bots that is. ^_^

5)Stealthy approach determines the winner

Stealth is important for CT coz they can make good use of their dark clothes. Hide in the shadows and carefully picking off a T with a sniper rifle. This strategy works well believe me. For T, I don't think they can be stealthy as possible coz of their bright clothes. Too bad...

6)Burst fire not happy-trigger

In this game, the physics counts and that goes for the bullets. If you keep pulling the trigger, the bullets will spread away and that won't hit an opponent if he is far away. But if clicking the fire button one at a time, the bullets are fired one by one so an opponent may get hit.

7)Conserve ammo or just take from other dead people

Ammo is very important here. If 90 seconds have passed you won't be able to buy it anymore. So, conserve them well. Let me give you a good tip. Assuming you are carrying a XM1014 shotgun with a total of  12 shells left. You killed someone who carrying a M390 shotgun. Now, drop your current shotgun and pick his shotgun. As you can see, your previous shells will be added with the M390. You now have let's say  20 shells. Now you can drop the M390 and pick up your old trusty XM1014. The shell quantity will be the same; 20 shells. Wu hoo! Extra shells no? This works with all weapons in CS not just shotguns! So, keep dropping and picking up guns to gain extra ammo!

8)Make good use of grenades

Know what type of grenades work. Smoke G for blanketing areas with smoke, Flashbang for blinding your opponent for a short time and HE G for blowing up certain areas. When approaching corners, throw Flash or HE G just in case if you suspect somebody is waiting behind the corner. If you see a grenade being thrown at you, run for cover or turn your view around if it is a Flash G. This way you won't be blinded.

9)Sound here and there

Sound plays an important role here in CS. If you run at full tilt, you make sound. Gunfire, well obviously make sound. Try to confuse the enemy by making sound at certain key locations in a map. When he try to inspect where the sound came from, eliminate him when you have the chance.

10)Spend money wisely

You should know which weapon you would want to buy depending how much money you have. Say if you have $4000 cash and you want to buy the XM1014 shotgun, that is risky! What if you die before you could fire a shell? That's just a waste of money. Try buying the Sub-MGs they cheap and light weighted. I will put a section where all the you gain certain amount of money when killing an opponent, rescuing hostages etc. soon. 

11)Hostage-mania

As you know killing a hostage would deduct your money from your account so being T, you can have the advantage from this fact. You just 'use' them so that they follow you around. Ok, now go out in the middle of battlefield and have the hostage surround you. This way, CT will have a hard time shooting at you coz if they accidentally kill a hostage, CT's money will be deducted. Then you can retaliate without any worry although if a CT don't mind losing money, he will simply mow down the hostages along with you, now that is another story....

12)Are you insulting me sir?

This tip is kind of RUDE but you see a sniper waiting for you and take you out when he has the chance, you INSULT him with words until he can't bear no more and will come down to kill you for good. But be warned that this method will get you kicked out from the game for sure....

13)Handguns trick

Ok people I got a very USEFUL tip that will ensure your sweet victory when using a handgun. YES, a handgun! This trick will work on all handguns but I recommend the powerful ones like Desert Eagle or Five Seven. Ok, so here's the trick: Usually you got to tap-click the FIREBUTTON1 to fire a handgun right and if you hold down the  FIREBUTTON1, the gun will not fire. Now, try pressing ENTER, the secondary  FIREBUTTON1 button. Just tap ENTER very fast and your handgun will shoot bullets like crazy. A reminder: you must be remained STATIONERY to this trick. If you have dual Elite Bereta handguns, well, fire away! ^_^

I will add more later...