If the pitch of the blades is not the same, then one blade will generate more lift than the other when hovering. This will cause vibration and steals power.
If the flybar paddles are not parallel to each other, then it may be impossible to track the main rotor blades properly. Ensure the flybar paddles are parallel to each other before adjusting main blade tracking.
Temporarily put a piece of bright colored tape on one of the rotor blades. This will cause the blades to be unbalanced but don't worry about this for now. Just remember to remove the tape after tracking the blades. You need this tape to determine which blade is higher or lower when checking the tracking.
Get a 6 foot length of 1" x 4" board.
Take the heli outside where the blades won't hit anything, and slide the board through the landing gear on top of the landing skids then either stake down the board or put cinderblocks on it. The board will hold down the heli in case Something Really Bad Happens.
Perform a preflight inspection and check everything.
Turn on the transmitter.
Connect the heli battery.
Arm the helicopter and slowly increase the throttle to about 1/4.
Walk a safe distance away, then get on your stomach, and apply throttle and look at the rotor blades from exactly the side. If both rotor blades are spinning exactly in the same plane and look like this: -o- then no adjustments are needed.
If both rotor blades are not tracking in the same plane and look like this: >o< then the blades are not tracking properly and require adjustment.
An alternative way to check the tracking is to place a mirror on your feet, then tilt the mirror so you can see the blades while standing up. This is considerably safer since your face will not be hit if the heli decides to throw a blade.
Shut off the throttle and wait for the rotor blades to spin down.
Disconnect the heli battery.
If the blades did not track evenly, then increase the pitch of the low blade and/or decrease the pitch of the high blade.
Go back to step 4 if necessary.