So the thing with advertising is that we need to finalize who our target audience is. With that list, we can then start brainstorming ideas that will help us advertise to our target audience.
Here's a rough list with examples of things we can do (feel free to suggest changes and additions):
1) Other FRC Teams (Obviously

): FIRST stuff, Social media
2) People in the community: Commercial, Fliers and posters in establishments around town, Social media
3) WHS Students: Social media, Little pranks around school (as Saty suggested), Decorations/Fliers and poster (like a big spider on a wall that advertises the competition?)
4) Gibbons and Elementary students: Social media, Decorations/Fliers and posters