Answer:
1st Sentence: Write what your favorite subject to photograph is.
2nd Sentence: Why and what do you like about it.
3rd Sentence: continue explaining what you like about it.
4th Sentence: Maybe an incident or some information related to that (evidence).
5th Sentence: Show how that's important and how it stands out. Say why you like it and maybe why others should like it as well (explain what you see in this subject that makes it your favorite).
6th Sentence: Write your conclusion which could include what subject you like to photograph. Summarize what you like about it.
Explanation:
For the conclusion, you can write something like this;
So in conclusion/To sum it all up, my favorite subject to photograph is _______ because of _________. It is a very beautiful subject (or write something like that). (And then here maybe put a reason why others should see the beauty/darkness of it or whatever you see in it). (Here insert some last thought/ lingering thought with your reader, something they can think about even after reading this but you want to make sure it's related to your topic.)