One of the best ways to show a business you're interested in their job position is with your voice and what you say. You need to seem like you want the job and not the money that comes with it. I personally think that businesses will hire someone that seems like they are interested in just the job itself--the money is more of a side thing to them. You should also go above and beyond, do everything that is optional for a resume or such document and spend time on your resume. You should also keep in touch with them, perhaps with handwritten, genuine, letters of appreciation.