Focus on anything you have that is positive. The greatest factor is having not only been active in the organization, but doing something to contribute greater than the level of the average member. Focus on that and 1 to 2 major ideas that you would like to bring to the table and/or changes you would make. Put that together in a coherent fashion and you should be golden.
If you had none of that, there's still a chance... You essentially just need to not be ugly and be able to BS your way through a speech. Most elections to a position are half popularity contest anyway. If people think you look like someone they'd get along with and would want to be around/trust, most of what comes out of your mouth won't matter anyway. Surprisingly, not many people attempt to run for Eboard positions, at least at the undergrad I went to.