Learn your map callouts - Every spot of every aggressive map will have names that CSGO Skins the community uses to informs you over voice comms that an enemy is not there. Normally these are obtuse terms that won't mean anything unless you know them - things like "generator" or "jungle" or "catwalk". It will take time to learn all the various callouts for all the different maps, but this info is essential for communicating with your team. Start here, and pick up the rest by listening to your team and asking for clarification when they call something unknown.
Learn how the CS economy works - Some of the chief things that makes CS strategically interesting is the way that money functions. At the end of every round, win or lose, you'll get some cash; the winners, of course, get substantially more money. Ensuring that everyone in your team has enough cash to be suitably equipped at the start of each round is a essential part of success in competitive games, and sometimes that means saving all your money and attempting to resist the enemy using pistols for a round, so the next round everybody has money to gear up correctly. Don't be the guy who buys throughout the round when everybody else is saving!
Often, these stains will ask that you bounce off the grenade a wall, or perform another trick to place the detonation precisely. There is a slew of videos which will show you all these spots, and show exactly how to throw your smoke grenade to get it to land there. Here is a movie showing the smoke and flash stains for de_dust2, CS:GO's hottest map. A quick Youtube hunt will find you similar videos for all the competitive maps. Once you know a number of them, begin an offline practice game and begin throwing some grenades around.
Find out when and when not to liquefy - If you have got a decent number of bullets left in Cheap CSGO Skins your magazine and think a enemy is close, don't begin reloading and get caught with your trousers down. Reloading takes time, and you need to only do it when you think you're safe from enemy fire. Should you run out of bullets in a firefight, switching into your pistol will be much quicker than attempting to reload mid-fight.