If it is long steep climbs and all you have are short hills, do repeats. I like to do drills where you time yourself on the first repeat and try to keep the time the same for subsequent repeats. This is harder than it seems, and requires you dial it back a bit on the first ones. I'd suggest hill repeats 2 times a week (not on consecutive days) and try to go one more repeat further each time than the time before.