As a basis for learning about realism use photographs.Focus on learning what you can.Action with materials = technique.Practiced techniques = skill.Habitual technique + skill = style.Continue with the subject matter you want to paint really well.That way you are continuing down the correct path (for you).Your focus is on portraits, landscapes, the sea, or whatever you like.Don't just select animals focus on one (tiger, cat, horse).Then even from the start you can become a specialist.Also focus on something you are interested in.This will help maintain the necessary motivation while you learn.Understand your animal, house, landscape, or whatever you want.Over time you will develop the individual paining skills needed.You will also know how to paint your subject your way.Eventually you can focus on another subject.If it is related to your original theme you will learn much quicker.From one breed of dog to another is an example.Then from one kind of animal to another.You'll note the similarities and also the differences.You could even progress from portraits to head and shoulders studies.Later these might be full figures.Follow this pattern for long enough, and you'll be able to paint anything!People who do things well are also faster than those who don't.That applies to painting just as much as anything else.It's one of the indicators of skill.By now you should notice that repetition helps skill development.Several small paintings are better for learning.Larger ones take more time and that's how you apply what you learnt.Skill in art, sport or even medicine is the same phenomenon.It's practiced behaviour in action.Most artists don't do anywhere near enough to develop any real skill.