This is the best video I’ve ever seen on squaring up a piece of stock on a mill. You’ll also see how a pro deburrs edges and see how quickly and smoothly he can turn the hand wheels (I don’t think he’s using a power feed). He also says you should start with a piece of stock that’s been cut so you’ll only need to make one rough cut and one finish cut on the mill. That sounds like a good advice if you have a Bridgeport but it’s probably not doable if you have a hobbyist-type mill because you may only be able take off .020 to .050-inches in those two passes. So your saw cuts (hacksaw, bandsaw, cold saw, etc.) would have to be very precise and square.