Incoming Service, why are arrows pointing away from service?
Correct way to indicate voltage is 120/240V for three wire and 240/120V for 4-wire delta; don't use a dash either way.
You've indicated everything that is new, why is the note in the lower right corner necessary.
You say to "install" new 125A/2P breaker. Does that mean someone else is furnishing it? Use either "Furnish and Install", or "Provide" if that's what you want. If I was a Contractor I'd hit you with an extra.
You don't have to use the word "Existing" simply use (E) if you want to indicate existing equipment. A good way to show that is to use screened lines for existing and only the new or modified work in dark lines.
Arrows off the text on left side come off top line of text, arrows that come off right side come of bottom right side of text
There's many ways to do it, but typically I think yo see cable information mor abbreviated as:
3-#8, #10G, 2"C. if you had parallel then (2) 3-#8, #10G, 2"C. If you have a spec then put cable type there, or in a sht note. If you don't care, then leave it off.
