Let me stop at this point and make a VERY IMPORTANT point. You MUST ALWAYS get permission IN WRITING to copy anyone's work!! It is protected by law and you could face very stiff legal fees and penalties if you copy their work. That being said, we can take pieces of work and use them, for example, if we like a particular clump of trees, the light in a photo, a house, etc it can be used, BUT NEVER use the entire photo or artwork without seeking permission first! Often we will be required to pay for the use of such material but usually not a large sum. In my case, I sought the permission of Steve Kaufman, Nature Photographer, to copy his photo of a panther in a book called "Wild Cats". Because this work benefits the Fl Panther, he kindly gave me permission to use his work and asked that I give him credit for the source (photography). Which of course I am happy to do!
If you are not comfortable with freehand drawing, another way of sketching or transferring the drawings to your canvas is to use graph paper to copy the art or object and then use transfer paper to add the drawing to your canvas. If you don't know how to do that. I will post an example for you when I post the paintings. I am also using a technique on the trees in this larger painting of the panthers that I think you will enjoy. Look for it and see if you like it!
As I make progress on my paintings, I am taking photos to share, and will post them. Thank you all for reading my posts and hope I am able to help you in your endeavors to become better artists. I was helped in this way by other artists, so I therefore pass it on.