In science, especially life sciences, research experience is often a must for graduating seniors. It will help you get a job if you decide to go into industry, look good on resumes for medical, dental, etc school, and is required when applying to graduate school. As a result, labs like mine, receive offers of servitude from hopeful undergraduates year round. Unfortunately for the undergrads, most of the grad students and post-docs, who would be directly mentoring you in the lab, aren't open to having minions. In my first three years of graduate school, I have taken on two undergraduate researchers, and had one high school student volunteer, and eight other undergraduates have worked in the lab for other mentors. Both of my undergraduates have done quite well, one will be attending grad school herself in the fall, and the other works as a lab tech for a biotechnology firm. Here are some of the things I look for and my considerations when taking on a new student.
I really cannot stress this one enough. When I first talk to a student some of my questions are: "How much time would you like to spend in lab?" "When do you have classes?" "What are your career goals?" "What do you want to accomplish here?" Now there's no perfect answer to any of these, but if you tell me you plan to work 30 hours a week in lab, and I see your class schedule will not allow that, then we are getting off on the wrong foot. The main reason for me asking these questions is not to see if you are a super science all-star that's willing to dedicate every extra second to the lab, it is to come up with a reasonable research project for you. If you want to go to med school, the only reason you're doing this is to get a good letter of recommendation, and you plan to maybe work twice a week for six hours, then I want to know that. I have plenty of jobs to give you that will only take up six hours a week, it won't be the most glamours side of science, but will both be happier then if spend our first encounter trying to sell me on how great you are and prove yourself wrong every week.
This ties in to number 1. I don't expect you to have questions about everything, but if you do have a question, ask! A big stumbling block I've seen others encounter is not being able to ask for help, and believe me you will get no points for this and the problem will not magically disappear on its own.
3. Realistic Expectations and Dealing with Failure:
Everybody starts off doing lab work and thinks they will cure cancer like tomorrow (I did too.) And everybody is wrong. Real science is not like the movies, it's a long hard slog of repetitive procedures that often don't work. A major reason graduate students and post-docs do not want to take on an undergraduate is that after experiencing this sensation once or for several months the undergraduate just stops showing up to lab and now I've just wasted all the time I invested in training that person. Now there's frequently no way that you can show me you have this ability before hand, but I will be understand if it's hard and going back to numbers 1 and 2, let me know and we can try and improve your situation together.
4. Not Grades:
The professor who's lab you want to join will always ask you for your grades, but I do not care. Earning an A in a course does not mean you know how to do things in the lab.
And really that's about it. Starting a career in science can be extremely difficult, but also rewarding, I hope you find a place that you fit and that fits you.