Many things can be done to an image to images in processing to improve them, but the best tip to improve wildlife photos is to shoot in bursts while in the field. An essential feature of a great wildlife photo is the animal’s expression. Capturing the emotion of wildlife is what creates a connection to your photos. Expressions make people relate and more fully engage with your photography.
Shooting in Bursts
What I mean by bursts is to take 3-5 images all at once. If you are trying to capture a bird in flight, then fire even more shots, to obtain the best expression. Sometimes it is not only OK to shoot a lot but preferable! So lean on the shutter release and get the expression!
In the case of birds, it will be an expression of flight as shown by the wing positions. When photographing mammals the best expressions generally have eye to eye contact.