Look carefully at the fittings on your specific bike tools to and be sure you have the right tools to work on them. Nearly everything on mine can be worked with a 4mm hex key.

I agree - take a bike maintenance class. You will leave with good notions about which tools to take and how to use them. most issues will be with tires. While I carry a patch kit, I also have spare tubes and fix the punctures later at home.

Also, carry a suitable FAK. The most precious bike component that can be damaged is YOU.