Packing cubes and judicious placement. So much easier to pull out a cube of clothing and slide it back in without stuff falling out of my suitcase drawer. You might try the slim packing cubes with handle and slot them in side by side like files, handles facing the top. Video here around the 9 min mark has a sample
https://www.travelfashiongirl.com/pa...to-pack-light/ I like to layer mine in stacks which requires me to take some out to get to lower layers.
+1 on top-loading suitcase and make sure there's top handle and bottom handle. You can grab the both handles to move the entire suitcase like a box without zipping up the top.