For any mandarin amateurs out there remember these tips.
1. They shouldn't be too big. Don't trust a large mandarin
2. There must be a significant gap between the skin and the actual mandarin the bigger the gap the better. It should be very easy to put your thumb in the top

3. Not juicy. Once you've peeled the mandarin it should look dry until you bite in to it. If the mandarin is juicy it'll either be too sweet or bitter
4. Heaps of seeds. If a mandarin has a lot of seeds this is very annoying

Keep these things in mind when looking for the right mandarin. Be careful out there, there are a lot of imposters! But most of all. Enjoy mandarins!