First, make sure your map abide the Ranking Criteria. Any unrankable issues found in the map should be either removed or fixed.
Second, you have to ask Beatmap Nominators (BN) to check your map and see if they have interest in pushing the map further. Having 2 BNs that agreed to push the set further is required.
or by looking at the modding forum, there're nomination queues there sometimes
tho you will need to make sure that your map is at rankable quality at the very least before using one of these ways to find bns, otherwise you're not gonna get anything ranked