Weak in the basics of Open Geometry

I have imported a picture of a small shoe buckle in the jpg format into an open sketch with Tools > Sketch Tools> Sketch Picture. I have sketched an outline over the perimeter of the buckle picture using circles, straight lines, and large radii via the three point arc tool, with the intention of extrusion. Even though I was careful to snap one arc to another on the red quadrant marks etc, I still have open geometry which prevents me from extruding the sketch. I also do not have smooth, blended transitions from arc to arc, due to snapping the end of an arc to a quadrant of a circle, rather than being able to snap it to "tangency". Now this has been a constant source of exasperation for me, obviously because I am weak in knowledge in this particular area. What I am attempting to do is to use the "Add Relation" tool to select one arc, CTRL select the adjoining arc, and make a tangent relationship, hopefully joining the two ends (closing the geometry), and creating blended smoothness between arcs at the same time. Well anyway I am getting WICKED distortion of my geometry. I have tried fully defining the sketch, which does indeed prevent the distortion, but then throws me into shark infested "OVER DEFINED" waters. Catch 22! Please tell me 1- how do I close the geometry and get a positive snap between lines, and 2- how do I create relationships without distorting. I really need to learn these principles of closing geometry because it is beating me up something terrible in trying to learn surfaces as well. I am prohibited from forming lofts, fills, etc. If someone could help me in this terrible weakness of mine, I would be most grateful. Erika