How small is your program and what state are you in?
The biggest mistake I see here in Ohio with smaller groups (under 40 kids), is that they try to do way too much. Competition does not attract kids/recruit for you unless you are successful. You are not going to be successful with no staff, and a very limited instrumentation.
Step 1: Hire a percussion instructor. Have boosters pay him/her if you have to, but marching bands need a percussion instructor. I can’t even imagine trying to have a quality marching percussion section without additional staff.
Look for band shows, college band days (massed band events on game day), etc in your area. Get the kids excited about being part of the band by making it “the thing to do”.
My very first gig out of college was a small rural school. The HS band had about 35 members in it when I started. We did band shows, etc until the numbers grew. By my last year (year 6), we had 75-80 members and were starting to compete. It takes time.
How many students are in the high school? How many are in the band? Is marching band separate from concert band?