Warmth and access to food they like may help them grow faster, cooler temps slow down growth. More adult females is the only way for them to reproduce faster. You can try feeding off only the male nymphs so when theh do reach adulthood you've mostly got females. They can be sexed before the final molt though it's impractical if you are feeding lots of little bitty ones.
Anecdotally citrus is claimed to boost breeding but since they have a long "gestation" period the limit is still your number of breeding females.