We found this guide to be helpful for placement: https://www.google.com/imgres?imgurl=https://taylorcraftdoor.com/wp-content/uploads/2015/04/Hardware-Placement-Recommendations.jpg&imgrefurl=https://taylorcraftdoor.com/cabinet-door-hardware-placement-guidelines/&h=3037&w=2337&tbnid=MELehP-ro2izBM:&q=cabinet+pull+placement&tbnh=160&tbnw=123&usg=AI4_-kQfN1lP1hFhpquDPtDty4Bm9LsF4A&vet=1&docid=RDesx2nY0TVRHM&sa=X&ved=2ahUKEwii0Pjp1p3eAhUIm-AKHdncCOkQ9QEwAHoECAsQBg
Aside from that, you just want to be consistent with what you do. We used a couple lengths of the same style pull. We did 6 1/4" pulls on the majority of our drawers and cabinets. For the two extra large drawers below the cooktop, we did 12" pulls. For the short upper cabinets we did 5" pulls (we have small cabinets above our tall pantries). We had one 12" base drawer that we had to do a 3 1/4" pull on.
We followed This Old House's tip to offset drawer pulls by 1/4 inch high for every lower drawer so they look balanced when you are looking at them from a normal standing height (so the first one is centered, the second one is 1/4" above center, the third is 1/2" above center and so on).
Q