If you are going to get your navel pierced you'd better find out beforehand which type of navel you have and which belly button piercing jewelry suits it better. The shapes of navels vary and there can't be two completely similar navels but there are some common types of navels and fitting types of belly button piercing.
The main types of navels include "innie" and "outie" navels. If you have prominent rim or lip your navel is "innie" and it is considered the most common type of belly. In such case the skin above the navel plug is pierced with a needle. "Outie" navel is usually a remnant of the umbilical cord and here the navel plug is usually used. But this type of navel isn't recommended for traditional piercing as it can be rather dangerous. Infection can immediately take place and travel to the liver. But there are ways out. The belly button piercing can be done on the bottom, on the top or on the navel sides. One can have several navel piercings.
In the lower piercing the lower ridge below the navel is pierced.
In the upper piercing the jewelry goes through the upper ridge above the navel.
The sides of navel can be pierced at various angles and you can have several punctures there.
You see that there are various variants of belly button piercing and almost each navel can be successfully pierced. Of course it's better if your belly is in good form because it will save you from crookedly healing, discomfort and other undesirable things.