Having trouble coming up with something to draw? No worries - while you'll eventually learn how to start from a tiny seed of a thought and gradually nurture it into a complex concept to explore through design and illustration, it's perfectly fine not to be there just yet.
For now though, here's an idea that might interest you.
You've all heard of the hammerhead shark - clearly the result of Poseidon leaving a mallet alone in the sea too long, and life finding a way. But what about the rest of his workshop? No mistake is destined only to happen once - so what strange sharks came out of his other tools?
Take a tool or utensil - you're not just limited to workshop items, consider tools that might be used in kitchens drawing studios, etc. - and use its shape/form language to help you invent a new species of shark.
Here's a quick handheld belt sander shark to get you started.
The Art of Brom
Here we're getting into the subjective - Gerald Brom is one of my favourite artists (and a pretty fantastic novelist!). That said, if I recommended art books just for the beautiful images contained therein, my list of recommendations would be miles long.
The reason this book is close to my heart is because of its introduction, where Brom goes explains in detail just how he went from being an army brat to one of the most highly respected dark fantasy artists in the world today. I believe that one's work is flavoured by their life's experiences, and discovering the roots from which other artists hail can help give one perspective on their own beginnings, and perhaps their eventual destination as well.