Service refers to extracurricular activities you might engage in that make a social contribution. This could range from volunteering in school as a senior tutor, working as an unpaid intern at a local hospital, or organizing a 5K run for charity. Any way in which you donate your time or talents to improve the lives of others around you constitutes "service." This activity should be performed without monetary compensation. Look for ways you can make a difference in your school and your community.
Character is perhaps the most difficult category to measure. It is informed by the other three criteria listed here, but is best demonstrated by evidence of grace under pressure. For example, struggling to achieve high grades with a learning disability might show your character. Honesty, reliability, concern and respect for others are markers of character. You might consider writing a modest letter describing your experience in character development to the nominating committee.
Leadership can be demonstrated by taking a decisive role in the implementation of a large project, such as the administration of the student council or creating a recycling program for the school. Leadership projects that are well-integrated with service activities are often more valuable than acting as the captain of a successful sports team. Look for ways that you can take the lead, particularly by creating projects that currently have no leadership.
Scholarship is demonstrated through high grades and a strong class ranking, or other exceptional achievements such as winning a state-level science fair. NHS members typically earn grade point averages over 3.9, so keep your grades up high. Because the nominations are locally based, participation in advanced placement and other honors classes is a wise choice.