1) It is ideal that with any new bike, the brakes be bedded in. When done properly, this will wear the brake pads and rotor together.
2) You will also want to avoid any sort of contaminants, such as oil from your hands, dirt, and debris, from getting on the rotor/pads.
3) When cleaning your rotor/pads it is best to use isopropyl alcohol.
4) You may also notice that brakes tend to squeal more often when they are wet. Keep in mind that some squealing is normal and its root cause is high frequency vibrations that are created from the application of the pads on the rotor. Having a smooth surface between the rotor and pads is ideal to lessen the likelihood of vibrations.