I might not get any PhD offers this year. I would like to apply again , what can I do to maximize chances

I am a mathematics undergraduate. I would like to get into a top 10 PhD school and might not do so this year. I would like to apply again and want to do what whatever is necessary to maximize my chances.

I have always heard that a masters in math is terminal and it might be too late to apply for one this year anyway(please correct me if I am wrong here).

What are my options?