well...i don't call myself a "Pro SMG" or something...but these are my experiences about SMG from 2 yrs playing AC:
1."Turn off your Auto-Reload"...hehe...I believe it's the first step to become a Pro...you can't believe how many times I have won matches just by changing my weapon to Pistol when i was out of bullet.(train it alot!)
2. "hold your aim down":yeah it's so important to keep it down...because controling SMG aim is hard.I think somewhere under your opponent's waist would be a good place to start shooting.
3."Jumping back while shooting"....I just learned it by watching Marriera's playing...I just found out this trick gives you more accuracy plus makes it so hard for your opponent to aim you.
4."Listen to you opponent's sounds":well...it's obvious that this tip helps you with all weapons...I have seen some players listening to music while playing...but i believe they can play better by listening to their opponent's foot steps...so it will be more easy for them to guess where their opponent is.And also try to make sound less,such as Reloading,so try to increase your accuracy in order to make less noises cuz of reloading.
5."Becareful":always be ready to click(shoot)...it's good idea to imagine your opponent behind every wall you want to pass.
6."You just need 7 Bullets".....yeah..you know whenever I shoot ,I just repeat it myself that this damn guy just 6 bullets to die(as if he wouldn't get kevlar" ...so0 maybe you wonder to see that without any reloading you can kill 4 persons with 100% accuracy. :O
7."Don't shoot the air"....well..i guess it didn't need to say..but sometimes i see some Pro guys shooting the air instead of their opponents...i guess it's just cuz that they are excited or shocked whenever they see their opponents.My advice is just to relax and calm down while playing.
8."Self Confidence"...hmmm....maybe it would be redicolous for you...but i believe self confidence gives you twice power....Always believe(and no just think), your opponent is dead before he kills you.
9."AimBox"well...this tip I just learned it a few days ago,I guess you all have heard about MyS using aimboxes.well...i did a little Research about it ,to see what it really is.=>
Aimbox is a hidden feature in AC ,that you can easily turn it On ,by typing a little command.The command is "/dbghbox 1".When you type this...you will see some boxes around all players(your mate,or your enemy" ...and this box show you the target you can shoot to hit your opponent.It's really usefull for far aiming...maybe now you all understand how MyS guys are all Gods with SMG.
anyway ,although its NOT cheating,but I just advise the last tip to use in Training your aims and not in matches.Cuz seems some other clans don't like MyS secrets