How much I cut depends on the pattern and my fabric. I prefer to cut out all the blocks and possibly sashing and binding all at once so I can label them. I usually wait on big outer borders unless I'm tight on fabric and want to be sure I have enough length, which is my preferred way to cut them. I sometimes carefully measure and square fabric then draw out a rough cutting diagram on paper so I don't mess up and run out of a fabric. I'm famous for that one! If I'm unsure of the block I cut out enough for one or two out of scraps so I can try it out and not waste big pieces of fabric.