To get ranked quickly in Google you will need a keyword with the Low Hanging Fruit Keyword or low QSR. You need to go for a keyword with less than 100 QSR/Competition.
If a keyword has high traffic and high QSR/Competition and another keyword have little traffic and small QSR/Competition, then you will need to go for the one with low QSR/Competition.
If it has QSR/Competition with time, it will ranked and then get traffic.