The best way is to keep building backlinks to your article page. However, you may want to check the competitveness of the keyword you are trying to rank. It will take time if the keyword is very competitive. The best thing is you are leveraging article directory authority which has high site links.
It is most beautiful to watch your ezine article move from the second page to the bottom of first page and then slowly move upwards to the coveted first three positions.