Reminding you of some tricks to use,
Do only half, create a Mirror modifier, make sure your Origin is set to the middle.
on the Mirror Modifier, make sure that merge and clipping are turned on.
then extrude and rotate to the angle desired,
On the Transform Orientation menu at the bottom, make it to Normal instead of Global, This way you can reselect the face of your extruded angle, and move it along a straight line of the same direction.
When the two mix they will merge and give you a nice look, then apply the modifier in Object mode and delete the face inside your middle junction (useless face anyway)
You could also just use the Grid, with Snap activated and make only a simple line drawing Vertices by Vertices.
To do so, make a plane, delete 3 verts, and use only the last one, then you extrude by pressing one of these after the E (X,Y,Z) to make sure it goes on the right direction, when you are satisfied, you can press F to fill the form, or create more verts with Subdivide, and make quad faces, you should leave the triangle face out until the end, and when you are done always make sure to Recalculate, and remove Doubles.
PS: A quad is a face with 4 verts.
Hope that will help you.~!