Drawing and editing curves in Adobe Illustrator can be challenging. If you have a Creative Cloud subscription, you now have a new, easier way to accomplish this task. Released with the October 2014 update, the new Curvature tool can be found next to the old Pen tool. Once you master the Curvature tool, you’ll be able to draw smooth, precise curves with little effort.
Take a look at Adobe’s tutorial on the new Curvature tool here: https://helpx.adobe.com/illustrator/how-to/draw-edit-curves.html?scid=social33203866&set=illustrator–whats-new–2014-10