How to leverage a "relevant experience"

Hey guys,

I recently accepted an offer at a startup company as a general business intern. The company is a contemporary lifestyle branding company that also do a good deal of manufacturing on the side. Since it is a startup company, my role is pretty free and I basically can help out in any way that I can. Ultimately, I want to work in IBD so I want to get some experience that would help my resume when I apply for internships next year as a junior. I'm sure I will be exposed to financial modeling of some sort and there will also be a good amount of bookkeeping duties. So my question is, what kinds of things should I involve myself in to best leverage this internship next year? Thanks!