

When making sketches on planes obscured by other 3D geometries you can slice the part which is above the plane of construction by selecting the slice option from the constraints panel while in the sketch environment as shown in the animated gif image below. If you want to temporarily disable the snapping to the nearest points, then press and hold the ctrl key and it will stop snapping to any point if ctrl is pressed. When making drawing in the sketch environment Fusion automatically snaps to nearby reference points.

When you type S in the sketch environment or 3D environment a shortcut panel will show up where you can search for the commands using the command name and you can even pin the frequently used commands on this panel for quick access as shown in the animated gif image below. Take the reference of the following animated image for more. You will get a menu of overlapping items, select your required object from this list. When objects like planes etc are obscured by other objects and you want to select the hidden objects then click and hold your cursor above overlapping objects. Take the reference of the attached animated gif image for more. Let go of your mouse click to again make a line. When making a line using the line command go to the endpoint of the line again when the command is active and hold down the left mouse button and move it outwards, it will now create an arc if the mouse click is pressed. To repeat the last used command in Fusion 360 simply right click hold your cursor and drag your mouse up as shown in the GIF image below.
