Here's a quick blog post/tip when working with Fusion 360.
It is well known that you cannot create an extrusion or revolution with a sketch that has an open profile. While in an active sketch Fusion 360 gives a graphical representation of a profile that is not closed.
The image below shows what a closed profile looks like!
Now, let's see how an open profile looks.
The red arrow points to a little white circle. This is Fusion 360 indicating that the profile is open in that area. If we zoom in on that location it becomes evident that profile is open.
We can now drag the end of one line to the other, or use coincident constraint to close up the profile and create the extrusion or revolution.