Is there some secret formula for staying organized?

The only pre-existing structure for keeping things organized in your pack are the pockets it has built into it. Ultralight packs often incorporate fewer pockets, since these require more fabric for a given volume. Beyond that you can add your own stuff sacks, Ziplocs and various ditty bags to help keep items organized. These also add weight.

So, the first decision will be how much weight is it worth to you to collect items into groupings, which are bagged up together so they can be more easily stowed and then found. A pile of loose stuff dropped into one big pocket is never going to be very organized. At the other extreme, putting every item in its own bag would be insane because it gains you nothing. You need to strike a happy balance.

For example, all the clothes I won't need during the day are in one stuff sack, which doubles as my pillow. First aid is in its own kit. Small emergency and repair items are together in a Ziploc. Food is distributed in gallon ziplocs with all my lunches together, suppers together and so on. Items I'll want quick access to go in the pack's lid pocket. And so on.

Then it becomes a matter of developing good habits. I tend to repack my pack from scratch each morning during a trip. This doesn't take as long as it sounds, because once everything has a home, I don't need to think about where it should go. I just grab it, stow it, grab the next thing and stow it, etc. I'm usually done in five minutes.

I hope this helps.