Dragon City Weakness List
The chart tells you which element is weak against which when defending. The first element of the dragon will tell you it’s weakness. For example, the Sea/Nature dragon Nenufar has Sea as it’s first element. Therefore, it will take double damage when hit by flame attacks and half damage from sea and nature attacks. It also takes no damage from terra attacks. This little chart is taken from the wonderful wikia.
Dragon City Dragon Attacking Guide
When attacking, you will want to see the basic elements and what it is effective against. Below is a quick chart to tell you the strengths and weaknesses of each element.
For example, a Flame hybrid dragon such as Cool Fire that has normal, flame and ice attacks would be very effective against sea, nature and ice type dragons.