Undergraduate / proper paragraph formatting for application essays [3]

What is the best way to format essays? I have them single spaced, but should the beginning of each paragraph be indented or should each paragraph be flush left, but with a space between paragraphs? The UC application, for example, won't let you indent the first paragraph - every time you save, it goes back to the left.

And what about short paragraphs, say with "dialogue"?

Thanks in advance!