I have been working on a pair of rats today and have really enjoyed the challenge.  Drawing is so therapeutic as well as being beneficial.  I have tended to get onto paintings as quickly as possible, working frenetically at the blocking in stage and fixing as I go.  This focus on drawing has been a breath of fresh air and by the time I am finished on this series I will be ready to focus my attention on painting once more.  The funny thing is that this sketchbook , being an expensive one, and one that is stitched rather than perforated, intimidated me a little.  Sometimes a book like this can make you feel that you can't take a chance because you might spoil it and then you can't take it out because it will spoil the book.  After almost fifty consecutive sketches I don't even think about making mistakes I just draw.  There will always be sketches that you prefer and those that you are not especially thrilled with but the progress is so worth it.  I can recommend setting yourself a challenge - maybe sketch every day for a week or every day for a month.  You could focus on a certain topic until you have exhausted it before moving on to another.  I prefer to take my own photographs or to draw from life but occasionally, when needs must, I will use someone else's photo.  Copying other artists' work is a good way to learn but it is something that I don't do, although I do study how certain techniques can be achieved.