That factor could be that every 737 feels a little different, one may have tighter controls, another might need more input to achieve the same result. Different loading is another factor of course. What I would recommend is to disengage the automation earlier to get a good feel of the airplane you are flying that day, then you should have a much better chance of a good landing
At the end of the day you just need to get some experience which is what your training is for. Good luck