Draw the stem of your leaf.
Draw a curved line for the left of your stem.
Repeat on the right.
Draw the veins in your leaf.
Choose a color for your leaf. Find dark versions of that color to start. Do not cut the paper, rip it. We want the edges to have interesting texture.
Glue your papers down as you overlap them.
Slowly start to lighten the color of your leaf as you fill the leaf.
Continue to lighten your color.
Fill your leaf.
Use a black oil pastel to redraw your stem and veins. Congratulations! You created a collage!