Sketching the profile
When creating a Revolved Boss/Base, only sketch half of the profile. And include a centerline.
For example, this:
When dimensioning a profile that you are going to revolve, dimension to the centerline and then move your mouse below the centerline to create diameter (rather than radius) dimensions
When drafters create drawings, sometimes they don't want to label the radius of 20 different holes or fillets if they're the same. So, they'll say something like 20 x R3.5 or R.35 TYP, where TYP means "typical" which just means "I made a bunch of similar fillets with the same radius.
If you ever need to create a pocket, the Offset Entities sketch tool is your friend. The cut below took like four clicks. Extrude Cut -> Sketch on face of part -> Offset Entities -> Click face of part -> Done.
If your first extrusion is symmetric about a plane, you're insane to not extrude it Midplane, rather than Blind.
You usually want your sketches to be closed loops, so SolidWorks knows what to extrude or revolve. But if what you're making has a uniform thickness, try a thin feature. Two examples below.
This open sketch:
And this open sketch:
And for the love of God...
Pattern features, not sketches.