You should be familiar with the industry and general information about the company, as well as the position you are applying for before your interview.
But to make sure you leave a good impression and can speak to points beyond general answers, it's useful to spend some time looking into the organization's mission and future goals. You shouldn't memorize these items, but be conscious of what they mean and represent when trying to work it into your responses - this will demonstrate that you are both invested in the company culture and objectives already, as well as being a good long-term investment.
Other key elements to try and research are: