First, lets us differentiate a nude painting from a life study.  A life study focuses on how human beings hold themselves.  It trains the eye of the painter to distinguish aspects of color, lights, and shadows.  And it provides opportunities for the painter’s hand to attempt various brush strokes. 

A nude painting, on the other hand, simply exalts the human form without clothes that hide or impede it.  A nude painting will always be a life study.  But a life study is not necessarily a nude painting.

Now that you have decided to create a nude painting, the next thing you do is to make up your mind about which approach to use.  If you desire to uphold the beauty and dignity of the human body, then you follow the classical tradition and be a Renaissance artist.  If you wanted to exhibit the strange, the exotic, and the mythical, then Romanticism will work for you.  If you wanted to portray an unbending truth with all its glory and squalor, Realism is the right approach.  

If you wanted to experiment and do not wish to be limited by conventional ideas about the human form, you belong to the circle of Matisse and Cezanne called Modernism.

The works of Renaissance artists has one common message to show to the world, and that is, “the human form is naturally perfect”.  They emphasized beauty and this beauty could be seen in balanced proportions and rhythmic vitality.  All other objects, that happen to be within the vicinity of the human subject, essentially lose their existence.

With Romanticism, however, such “objects” are given importance, along with the unclothed human body.  This is why nude paintings of Romantic artists also show a strange world, which may be based on fables, myths, or history.  Mystery is an important element.

In Realism, truth is the most important concept.  Truth could be humility, shame, subservience or anger.  This movement defies the idea of beauty of the human form and it shows that the body of an average person is never perfect and certainly not pleasing to look at.  And so, if you ever make a nude painting with this approach, your masterpiece won’t hold much appeal at first glance.  But, like wine that has been aged, it becomes more and more fascinating.

For modernists, the human form need not be displayed as the way a human eye sees it.  The unclothed human body could be painted the way the mind, the heart, or the culture sees it.  And so, there are impressionists and cubists.  If you go for this, you would find it easy to find an original presentation.

Yet, why be limited with the approaches listed here?  As an artist, freedom is part of your life.  Your choices are limitless.