This big book is chock-full of step-by-step diagrams to draw common backyard animals, native wildflowers, trees, and landscapes. There are also journaling helps on making a map, diagramming birdsong, keep lists, and estimating numbers.
When I am stuck on how to draw an animal or plant part I turn to this book.
Here is an example of the guidelines that the author explains in this book. He focuses on using numbers, images, and diagrams. I posted information on this style here.
If you are just starting out this book is great and easy to use. The focus is drawing and creating attractive nature journal layout.