Does the sight of all these high ranks look intimidating? If you go up against these guys and are intimidated just by the sight of their ranks, you practically lost the battle already.
Let us analyze first what these players are better at then us who just started playing the game. The first thing we must consider is their shooting speed. A very good sniper can quick scope a just-spotted target at 0.13 seconds; that is about 1/10 of a second (anything faster is wallhack). that is enough to frighten an unsuspecting player. A newbie who just started playing the game 2 hours ago would most likely have a shooting speed of 2 or 3 seconds. Compared to a veteran player, a newbie would literally shoot 20 to 30 times slower.
The second factor we should also take into consideration is accuracy. High rankers may have astounding accuracy. with an M4 rifle ( I will use this gun as my basis for explanation because it is the most versatile assualt rifle), they only use about 6-8 bullets to kill an opponent while newbies who just started playing 2 hours ago would use an entire clip vandalizing walls, floors, and boxes with decent black holes leaving the opponent unscathed.
A kill is more dependant on accuracy then shooting speed. So if you are a new player, vie more for accuracy. Take your time to aim, relax, and make sure that all the bullets hit their mark.
They have decent shooting speed and accuracy, how can i beat them?
At captain rank level, you may be joining other clans and ask, "who is the best sniper around?" or "who is the best sprayer around?" and you may do anything just to have a match with that appointed player to beat him, pulvurize his reputation and make him/her kneel before you to acknowledge that you are the better player. That is a very good attitude, and if you have that confidence, you have a high chance to defeat the high ranking players. If you feel scared and unconfident of your skills, keep practicing until you are more confident.
So you have the confidence but you may still ask me, Why do i still lose against that bastard high ranking nerd?
A good player uses his brains to outwit the enemy. A good player may hide behind boxes for cover, hide half of his/her body behind a corner wall while waiting for oncoming enemies. They may throw granades at the far end of the map so the enemy would look towards the area of explosion, while they slowly creep from the opposite side to stab the enemy unsuspectingly from behind. A good player makes decisions based on the enemies way of thinking.
Let me give you a few examples of tactics i know:
At the first round of a match in shang, I wouldnt throw my window grenade from redbase to blue office window yet; I wait until the second round. This is because the window grenade throw is so common and considering their high rank and experience, I know that they wouldnt dare approach the window. But when they realize that no nades where thrown at the first round, what will they think? They may think "these guys dont know how to window grenade" so they try to take advantage of that. 4 snipers may confidently approach the window, fighting one another for the better view, while i would throw my window grenade and kill them unsuspectingly.
Another example was when I (a sniper) was on a 1 on 1 end-game-team-battle with a sprayer camping inside shanghai warehouse B (Close to the submarine). I heard him walking inside the warehouse and i assumed he was camping in the middle behind a box. I knew that in a frontal combat, my chances of killing him would be slim without the element of surprise. I continued k-walking down the middle alley (near green container) towards the warehouse and switched to normal walk when i was going towards the left side of the warehouse (where there is a box next to the door). What did the enemy think at that time? Most likely he thought i went in the direction of the sound i made. But I quickly k-walked to the opposite direction where i meet him slowly k-walking hoping to get a glimpse of my backside, but to his surprise i was facing him and ready to shoot.
The SF battle field is not only a battle of shooting speed and accuracy, it is a battle of minds where the smarter one comes out on top, so if you face an opponent who has godly shooting speed and accuracy compared to yours, dont be intimidated; be confident in your skills, and use your mind to devise cunning tactics to outwit the enemy.
I believe when you are against someone who has insane reaction time ("skillz" "1337" "h4x" koreans"

, you really have to put your knowledge of the map to good use. A good, smart player will beat a "pro" player who doesnt play intelligently.
I once encountered a player who had his headphones volume on max. So reloading weapons would tip him off on your position...(the sound your gun makes when you push the magazine in)
Just do constantly fake reloads(press f twice) and come running at the guy, who would be k walking with his knife/pistol.
Probably only works against pubstars, but its a neat trick nonetheless.
If you have any other tactics you wish to share with anybody, you are welcome to post it at the comments of this page; I will then add them to this page for better viewing