Here is a little exercise that I like to do to quickly get some ideas on paper. I choose a few images from my reference folders-in this case a turtle-and I just start to sketch the first thing that comes to mind. Once I finish the first sketch (1st on the left) I continue on to the next two with a similar theme in mind. I use the turtle itself for different ideas and design elements. If I end up liking any of the sketches, I can always go back to them later and polish them up a bit. This is a great exercise for when you need to quickly get some concepts done for a client or director.