Use a good "brain sheet."
Make a grid/table with each patient across the top and each hour of your shift down the side. If Mr. A. needs a med at 2100, write "med" in the box where Mr. A. and 9pm cross. If Mrs. B. needs a glucose at 0500, mark that, too. And so on. If you see a huge cluster of things that need doing between 2000 & 2200 and again at 2400 and again between 0500 & 0700, that gives you an idea of how the shift will flow. If three patients need something at 2400, you'll probably start with the first one at 2330, get to the 2nd at 2400 and the 3rd at 2430. Anticipate what your patient may need. If Mrs. C. gets a diuretic at 1800, just plan on her needing to potty a bit later & mark that on your grid.
Cluster care: when you go in to give the 9pm med to Mr. A., bring some stuff to stock the room/linen/supply cart, give the med, do his assessment, toilet him & get him tucked into bed, if he'll let you. "Can I do anything else for you?" is not just for satisfaction surveys. It also helps keep people off the call bell.
Remember that the best-laid plans do not always work out and sometimes the whole schedule just goes to pot.
OH, and if things DO change, flex with it. Mrs. B's shortness of breath at 2000 is going to be prioritized over Mrs. C's full bladder.