This is something that I learned in my class on writing literary criticism:
To see the pattern of your sentences and how long they are, wherever there's a period make a dot on the margin. This way, you can visualize the length of your sentences and see what areas are either lacking in dots or abounding in them. And, this doesn't take up a lot of your time (it's the whole fixing it that takes longer).
This helped me a lot in writing my essay, because it's important to have a lot of different sentence lengths when writing an essay. And in general, I think writing creatively a variety of sentence lengths is good, unless one is making a point with the length of syntax.
Just something quick I thought I'd share. :)