What kinds of extracurriculars does CalTech look for? Competitions, research, etc… My school offers little to no science ECs and I am not sure what I should aim for.
There’s no formula to CalTech admissions.
Work with what’s offered to your school and apply to outside things like RSI, Jackson lab summer internship, etc. If you’re genuinely interested in something like Science Quizbowl or Ocean Bowl, you could try to start one at your school, but don’t start a club just for resume padding.