personally I measure, mark, mark the offcut with an x, then on the saw I'd be looking to just remove the pencil line with the blade and no more. I don't think that there is a right and a wrong it is just important to measure and cut with the same thought process.
Once I was happy with the length I'd then possibly set up stop blocks for repeating the cuts if needed. You also need to think about sawdust building up on the saw, brush or blow off the surfaces regularly , and take the bottom corners off the stop block so the sawdust can push out of the way and not throw off your measurements and angles. possibly not explaining that well, this video explains...