You can start fresh or continue on the same line you have: so first off, delete any vertices in between the line, so that you have only 2 vertices (one on the top and one on the bottom). Using the MOVE tool, move one of the vertices where you want it to be. When done, use the REFINE tool and add a vertex on the line wherever you want it to be. This one vertex is enough to get the outline you want so exit refine mode by right clicking on the viewport twice.
Select the new vertex you added and right click over it, and from the menu that appears, select BEZIER if it's not already selected. You'll see two handles on the vertex, and now you can move/ rotate (try them both) these handles until you get the right shape.
If you want more control over these handles, You can right click on the vertex again and select BEZIER CORNER instead so that each handle is independent of the other.
If you have used Photoshop, then it's akin to the PEN tool in Photoshop.
