Do you have any publications? If not, is there any chance you can try and get your Masters thesis published? Oftentimes when you submit an article for publication, and it is accepted with revisions, those revisions will help you to polish your writing sample and will make you a more competitive candidate.
Also, I would suggest getting a bunch of word lists and really studying hard for the verbal section of the GRE- your math score is great, but your verbal is a bit low and may have hurt you during the application process.
Other than that, you should e-mail all of the programs you applied to this year and ask if they had any suggestions for you to strengthen your application for next year. I'm sure at least one of them will respond. I don't think there's much you can do about appealing to the programs that rejected you, but contacting them and asking for advice on how you can be a more competitive candidate will show your continued interest and may help you out next year.
Good luck!