When it comes to speeding up an activity, there are various ways to express the idea of "pick up speed." One way is to use the phrase "gain momentum," which implies that the process is starting to move forward with increasing force. "Accelerate" is another appropriate synonym for "pick up speed," as it suggests a swift increase in speed. "Ramp up" connotes a gradual increase in speed, like a ramp starting small and increasing in steepness over time. "Quickening" refers to a gradual yet constant increase in speed, while "hasten" implies a deliberate effort to make something happen faster. All these synonyms offer different shades of meaning, depending on the context in which they are used.