I couldn't find any threads specifically on it, so I figured I'd write some tips to help my bored mood at the moment.
Recently, I have used the AK-47 more than ever. My main assault rifle of choice (when playing as a terrorist, of course) had been the 552, but lately I have been using it less and less. I like the AK for various reasons. One, it is pretty powerful. It will take someone down with ease. The look of it is a classic terrorist appearance. Hardly anyone uses it, but you can find ammo on dead bodies quite easily. Also, the sound of it is very deep and distinguishable. Since not many people use it, if it's heard, the enemy know someone with skill is behind the trigger.
When I choose the AK, I only equip it with a rifle laser. Even if I am playing on CA maps, I still leave the extended clips attachment off. I don't need more than 30 rounds to bring someone down. Because I only use the rifle laser, my weight is greatly reduced, allowing for either heavier equipment to be carried, or the ability to move faster, which is a great advantage.
The AK only has two fire modes: semi and fully automatic. About 90% of the time I will have it set to fully automatic. However, if a target is far away, I will throw it to semi and take my shots. Although I do not have a scope, I have found that firing one shot at a time when on both modes, the accuracy is increased when it is on semi. I do not know if this is a fact, or just my interpretation, but it works for me.
If you find yourself engaged with someone, the AK can hold its own if you do not let up on the trigger. However, if you or your enemy gets behind cover, do not continue firing. Much like any situation, if you continue to fire on the enemy while he/she is behind cover and you are not, chances are they are reloading, waiting for you to be empty. When directly engaging someone, your best bet is to fire away. Not much can be given on aiming, at least when talking about special hints for the AK. Aiming is just like any other rifle, aim for the chest.
Perhaps you come behind an enemy, and they do not know it. Depending on distance, I would drop to a knee and fire in short bursts of two or three. If you can, try and get closer, just to ensure your kill, although if your aim is on target, you won't need to be. If your target is further away and you do not wish to persue them, flip it to semi and fire at their back/chest. It does not matter how fast or slow you fire the AK on semi, the accuracy stays about the same. I don't try and fire as fast as possible with a target far away, though.
That's all I can think of at the moment. If you don't normally use the AK, try it in your next game. We all know that sometimes some guns don't work for us, so if you fail the first time, give it a second chance. Many times after a game is finished and we are in the lobby, I will hear positive comments about my use of the AK. Of course, this is only if I did well.
I hope this helped anyone in search of a new assault rifle choice. I don't know how many of you will actually try it, but it is definitely a weapon that should be given a chance.