Strong communication skills are important. Scientists spend a lot of time writing papers and giving presentations.
You might want to take a course at a marine science laboratory. Such courses are offered by many schools around the country and would give you excellent laboratory experience.
Internships are a good way to gain experience. If you think you might want to do this, it is best to start looking in your second year of college.
A strong, broad-based science background is a better preparation for graduate school than one that is very specialized.
Most researchers spend at least some time each year engaged in fieldwork. This may involve time on a research ship or other vessel.