FAULTS: A fault committed by the player or side serving: Before or during the serve any player feints or balks the opponent. - my opponent was saying that my serve is at fault because it feints her. Because i wiggles my racket slightly (in forward and backward directions) when serving. The wiggling was very slight, but the opponent stated that it distracted her because it makes her think it looked like i'm going to do a high serve, but i actually only did a short serve. Does this kind of actions called a fault?...it's just simply my style of serving!
As long as it is one smooth motion from the time you start your serving sroke, to the time you finish, you are not at fault as far as I know.
This is tough to say for sure because we'd need to see the actual movement but in general, if it's bothering the opponent, I'd say it's a fault in a normal, friendly game. In a sanctioned game, it's up the the powers that be, a judgment call.
You cannot make a "forwards, then back, then forwards again" motion when serving. You can wiggle the racket from side to side as much as you want (why bother?), but not forwards and backwards. The first forwards motion of the racket head towards the shuttle is defined to be the serve, and it must continue forwards without interruption until you hit the shuttle.
some players (e.g. Eng Hian) hold the shuttle just behind the racquet. Then they move the racquet head forwards and backwards (all in front of the shuttle) and then at some point a backswing comes behind the shuttle and then they serve. There is only one "forwards motion of the racket head towards the shuttle" so it does not break that rule, but it could be considered distracting. They do not get faulted for it though. Wiggle the racquet back and forward when it is behind the shuttle though, that is a fault.