When contacting high schools in your area, ask to speak with a teacher in charge of Career and Technology Education programs. Contact schools that are reasonably close to your business. You'll be helping your immediate community and saving your interns travel time that could be spent at your company. Teachers will use it to find the best candidates for you. Develop an application form for your internship position and provide it to the school.
Companies often use or adapt their employment application form.
Finding the right student for your internship takes some planning on the part of the schools. Do your best to give them adequate time to select applicants for your internship. The school may select several applicants for your internship position. You or your committee should review the applications and select the individuals to be interviewed. Interview prospective interns just as you would a prospective employee.