I am a student and I made an illustration with illustrator. As you can see in the example I made, it isn't the best illustration and It can be much better.
As you see, I gave the rocks underneath the lighthouse some sharp edges. I put some movement lines in the water. Some shadows. That's all. I don't know where to put more details into my design. It feels the design is missing some elements and I don't know what.
Basically my question is: How do you when, where and what to put some 'subtle' details in your design to improve it ?