Go smoothly is a phrase that can be used to describe a successful and effortless process. The crossword solutions for this phrase are SAIL, HUM, GLIDE, SKATE, and FLOW. SAIL is an activity where one uses a boat to travel across water. HUM is the act of making a low, continuous sound. GLIDE is the act of moving smoothly and effortlessly. SKATE is an activity where one uses a skateboard or ice skates to move around. Finally, FLOW is the act of moving in a steady stream. All of these activities involve smooth and effortless motion, which is what the phrase 'go smoothly' implies.