Start by understanding the formal elements of art. Use those to analyze composition.
Then go beyond that and try to understand what makes each photo elicit the emotionally reactions they do.
With Leiter, colors are a huge component. Look up color theory if you need to have better tools to analyze that.
Lighting is also important to understand, to get a better technical understanding of how the results were achieved.
All of it will influence your work one way or another. But make sure you don't get in too deep with only one artist. Try to diversify the art you're exposed to, in order to diversify your influences.