In an attempt to improve my painting skills, I recently took up drawing after buying a book on vacation in Bangkok about street sketching. After giving it a few tries, i really enjoyed the concept of drawing people or things in front of you. For instance, as a general practice, I tried to draw the person next to me on a bus ride.
Most of the time though, I have tried to draw celebrities by watching tv or pictures. This makes it easier to decide if the drawing actually looks like the real person or not. I also hope to some day be able to paint people by free hand, and would think that these kind of drawings could help me to also improve my painting techniques.
The more I draw though, the more I actually enjoy the sketching in itself. It is a great way to keep improving my skills, without having to pull out all the equipment you need for dooing paintings. An easier and fun option if you have less time to spend, or are traveling around.
I guess the most important tip I´ve read for sketching so far, is to draw what you actually see and not what you think or expect to see. This helped me a lot for the drawings above. I sure got to use my eraser though.
Here are some more of my sketches: