Dont be afraid of the blank paper. Dont be afraid of no knowing what to draw. Be kind to yourself and allow yourself to expierence your subconscious mind. Try to feel which lines makes you feel good which makes you feel uncomfortable. Try to take this experience to the next sketch. Dont judge yourself. It's just a sketch, just lines on a paper. But still maybe those lines and sketches can lead to something bigger than in your imagination. It's like exploring a new place, without knowing what to expect. You dont know what will come out of this. But you can trust on one thing the more you do it the better it gets. So just enjoy the ride.