Great Megalodon Shark

I've just started out recently. This image my intention was to get better with understanding colours and putting together the various shades to collectively form the image. Looking to improve step by step.

"It’s a puzzle piece that has eluded shark scientists for years: just why exactly did the ancient Otodus megalodon, the largest shark to ever swim in our planet’s oceans, disappear? While recent movies and mockumentaries have toyed with the idea that “the Meg” is still alive, it is unquestionably extinct according to marine biologists. "