I recommend writing a sentence, going to the next sentence and writing that one, and then going back to look at that previous sentence in light of the next sentence. Rewriting the first sentence will improve it, but then you will probably need to rewrite that second sentence again so that it does a better job living with that new, rewritten first sentence. Then go ahead and do a third sentence, but be sure to get a chance to revisit the first and second sentence at least two or three more times, and then revisit that third sentence, as well.
I recommend writing a sentence, going to the next sentence and writing that one, and then going back to look at that previous sentence in light of the next sentence. Rewriting the first sentence will improve it, but then you will probably need to rewrite that second sentence again so that it does a better job living with that new, rewritten first sentence. Then go ahead and do a third sentence, but be sure to get a chance to revisit the first and second sentence at least two or three more times, and then revisit that third sentence, as well.