Organize an interest meeting to determine how many people are committed to bringing a program to your school. Contact your local newspaper and radio station, asking them to promote your plan to the community. Invite people of all ages who are interested. Adults who have played previously are a valuable asset.
Approach the school board with your request. Most boards run on a strict budget, so be prepared to present your program idea without asking for funding. Offer to start very small, with students providing their own instruments and meeting after school. Ask only for use of the band room, or another location.
Find an adult volunteer conductor from the citizens at your original interest meeting. This is a big commitment for anyone, so treat the conductor with respect.
Start small. Perhaps a string quartet is the best you can do for now, but as interest grows, make it a quintet and keep adding musicians.
Arrange to play publicly as often as possible. To enlist support for your orchestra, you need the community's backing. Offer to play for chamber of commerce luncheons, awards ceremonies and other events. Always dress appropriately and conduct yourself with decorum.
Return to the school board to request funding when your orchestra has grown in size and you have a lot of community support. Approach your needs one at a time. Compensation for the conductor, use of the auditorium, the purchase of used instruments for students who don't have their own and music stands are all valid requests. As your popularity grows, so will the board's willingness to support you.
Promote a beginning orchestra in middle school after the high school orchestra is operating at full speed. You will have a larger supply of quality musicians to choose from when they enter high school.