Do's and Don't's of Undergraduate Research?
Ask plenty of questions and write everything down. If you do not write notes when someone is explaining something to you, it will be embarrassing to go back and ask them a second time to explain it again. Before you get to the lab I would locate/Ask for review articles related to the project. Realize that you will likely shadowing a senior person while you are there, adapt to their schedule. Don't spend your incubation times face booking. Use this time to build relationships with others in the lab and on your floor and try to absorb as much information about the way the world of science works. Speaking from personal experience the small things you learn there may be insignificant but may come to be important to you in the future. If you have your own project, realize that it will probably be a small one attached to a bigger project another lab member is working on. Thats a good thing, because your time there is not long enough to get into something complicated. A simple, clear, and focused question will be key to your success. 

What you should take away from the experience is not necessarily something that will amount to publication, but the actually experience in the actual process of designing experiments, performing them, and analyzing data. Assuming you are doing this to help prepare you to go on to work on a graduate degree in your favorite area of biology then remember that this is here to help you get to the next level. Programs like this allow you to demonstrate that you understand what it takes to perform graduate-level work, and potentially become a successful scientist one day.