There are many levels of involvement. Some of those include becoming familiar with the issues by reading about them in newspapers, magazines, journals, and websites such as this one. Equally important is to remain vigilant about current legislative affairs, contacting legislators at both state and federal level, voting with clear knowledge and a conscience attuned to the life issues, and engaging in Life Chains, prayer vigils, marches and rallies. Try finding a crisis pregnancy center near where you live and volunteer to help save babies' lives and support women in difficult circumstances.
Also, passing on information to friends will help educate many more citizens. Finally, it is helpful to support pro-life organizations financially, as none of this work gets done otherwise.