You can greatly improve your drawing skills by practicing with landscapes. Sit outside and draw in forests and parks or work from pictures or your imagination inside. Drawing landscapes will help you with perspective and rendering the many different textures in nature. Drawing convincing tree bark will help distinguish the tree from its leaves, the grass and other surroundings. Tree bark comes in many different textures, but once you have learnt the basic technique, you will be able to draw various tree species.
Decide on your composition, or how you plan to lay out items on the page. Look at the space and size of the scene. Decide if you would like your tree in the centre of your still life, or elsewhere.
Observe the tree closely. Lightly sketch the outline of the tree trunk and branches on your page. Note that trees are rarely perfectly straight nor do they have right angles. Do not draw leaves in individually, but rather separate them into larger shapes, disconnected by sky and branches.
Examine the tree trunk closely. If you are drawing from real life, go up and touch the bark to get a better view. Decide if the overall pattern of the bark is vertical, horizontal or in cloudlike shapes like a sycamore. Lightly draw the outline of the general pattern of the bark. Remember to vary the pattern so that it looks random and natural.
Look to see where the sun is in the sky, to the left or right of the tree trunk. Use the side of the pencil point to lightly shade the side of the trunk opposite from the sun, growing lighter as you hit the bright side. You can shade by hatching, drawing lines in a single direction, or cross-hatching, building up darkness by layering lines in multiple directions.
Add depth to the bark texture by shading. Press a dull-tipped pencil hard on the paper where you see shadows and use thicker lines to distinguish shapes. You can leave the highlights on the bark white, or shade them lightly with the sharp point of the pencil. If the bark is smooth, like a sycamore, lightly shade in the shapes to mimic the colour changes on the bark. If you make any mistakes, erase the extra marks.
Darken in knots of the wood, if you see any. Most trees do not have knots in the trunk, but rather at the creases of the branches. Use a dull pencil to completely fill in the knot with dark graphite.
Add colour to your still life if desired. Coloured pencils and chalk pastels work well in conjunction with graphite. Colour over the graphite so that it can peek through. Depending on the tree species, use shades of brown, grey, purple, red and blue.