Now that you have the image transferred to your work piece you are ready to start burning.
My first suggestion is to pick a piece of scrap wood that is the same kind as your project to use as a practice specimen. This scrap piece will be used to determine heat settings and profile or pattern that your burning nib will make.
I mentioned heat settings and this would apply to a burner like the one pictured below. To produce high quality intricate art or designs it will be difficult to achieve without one. So save yourself a lot of frustration and move to this type of burning unit right from the start and you will be glad you did.
Then I study the color photo and grey scale picture I created the pattern from to determine what burning tips I will need for both shading and detail work. Taking into special consideration how the light is hitting the animal and orientation of the shadows.