Or grab a sheet of paper and just keep drawing - ifs its bad don't rip it up carry on drawing over it or beside it. Keep going till the page is full and start again. I got loads of scrapbooks full of drawings at home - some pages are good some are rubbish and some are a mix. Beauty of this is if you look at a page you can see how you developed. Plus xyzz dude is right - its self esteem too. If you go nah its rubbish and stop then you wont get good. Which is why the above method is good. So keep drawing - I'm in my early 20's and I still draw all over the place - even at work - sometimes on quotes that I have to send to customers.