One method to keep in mind when trying to make a smooth curve from points, is the function "Arc from 3 entities." It can make a much smoother model (depending on what you are trying to reverse engineer) than simple lines. Sometimes after you get this arc, then you can verify it to find out its radius, and then decide whether it should be an exact value (to fit some standard part) and modify it, by drawing a new arc of the correct radius, and using 'sketch' to place the new arc in a best fit near the 3 points that were used to generate the original arc.
First you get good, then you get fast. Then grouchiness sets in.
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)