Always try something new in your drawings
First of all this is not obligatory. Everyone has their own style and not even greats like Picasso or Dali did something new in every single one of their paintings. It’s just to persuade you to keep your eyes open to new things to draw or paint, don’t get stuck by one subject or topic (like painting dogs in dresses only) but be open to paint other things too. Also it’s good to try new techniques in drawing or painting, let it be shading, the reflection of lights, using more or other colors, or drawing in black and white. Other examples include contouring or applying less contour but the list is extremely long.
Remember Picasso did not start with cubist paintings, it took him multiple decades to get there and create according to cubist style. And even then, he went on and painted or drew in other different ways as well. Getting stuck is not good for any artist. So, relax and be open to change your style and experiment with new techniques from time to time.