Best way to draw a set of plans is to take the lines off an existing vessel. It is a demanding task, requiring organization and precision. I describe the process - for my Scooter - on my site. Scroll way down to "Measuring & Drawing" and Gallery 13.
Another approach is to start with plans from a similar boat. Eric recently posted plans (from Chappelle's American Small Sailing Craft) ) for a Delaware Ducker. Here is another source:
The key to the flare you are looking for is the shape of each "section" - a cross-sectional scaled drawing.
The Ducker is deeper, beamier and more "burdensome" (designed to carry a heavy load) than the vessel you show. However, with a set of plans to start with, you can adjust key dimension as you see fit.