One of the exercises we obsess most about in aikido is the walking exercise - also known as tegatana or tandoku undo or unsoku, etc... This exercise is complex enough that we are always making little adjustments and tweaks to try to get the thing right (whatever "right" is - nobody's ever achieved it yet).
One of the interesting properties of this exercise, is whenever you focus on correcting or improving one particular aspect, much of the rest of the thing falls into chaos. Sorta like trying to stack sand into a pyramid - you try to put one grain in the right place and half the pile sloughs down the side and you have to start re-building the whole thing with that one grain placed properly.
Lately I've been focusing on getting off my heels so that I'm bearing my weight on the balls of my feet. Actually I thought I'd always done that but I'd become lax and my heels had been bearing progressively more weight without me noticing. So, I've been focusing on getting off my heels and the rest of the thing has fallen to chaos.
Today I think I'm ready to try to get weight-off-heels and another piece right at the same time! Yay me!
So, for a while we'll be working on bearing weight on the balls of the feet and living where you land. That is, when you make a movement, you've got to attempt to deal with wherever you placed your feet - no extra little weight shifts to try to get a little more comfortable on your feet. You've got to either place them correctly the first time, every time, or learn to live where you've landed.