We became members of the local zoo so we could take the grandkids there often, without breaking the bank each time. They publish a magazine with great photos of all sorts of critters. It's an easy way to get some extreme close-ups and some exotic species. Had an art instructor in college who stressed getting to know your subject; if you were going to draw a picture of a cat, he'd want to know how many wiskers the kitty had, and you'd better come up with the correct number! Your montage brought that to mind. Keep drawing!
Any drawing practice has got to be good for you. The more you do it.........the better it becomes.
If I could suggest getting a couple of cheap basic drawing books. These will help you to break down forms like animals etc into shapes...they will also instruct you how to use help lines to build forms up with.
Get a basic drawing book and really look around. there are some good ones that are specific to animals....or even animation books are excellent. A lot of the more expensive books can be too much information of which 99% of you'll never use. There used to be a series of "Walter Foster" books which were great!!