Sometimes one character speaks to you more often than others, and usually says something along the lines of, ‘hey cosplayer, make my other costumes too!’
When I know I have a situation like this, I like to take time during the event to note what parts of the costume are working, aren’t working, and what ways they could be made better from either talking to other cosplayers or simple realization after the fact. I think that doing this while actually being in costume, as opposed to doing it after the event, is helpful because the little things get remembered as well as the big things.
For example, Dissidia Final Fantasy Kuja has two outfits, but unlike some of the other characters, it’s the same outfit (essentially) in a different color scheme, making it easy to improve upon the last costume. The list has since grown to include style differences between the two costumes, but still contains points like:
4. Non-fusible interfacing with collars
5. Different material for shoulder armor than for trim, curvier shape. Amendment: fiber mache
12. Getting into costume would go much faster if the decorative buckles up ‘front’ were not also actually holding up the skirt ensemble
As you can see, some of them are comfort issues, some of them are me falling out of love with my material choice, and other notes. Even if a character has different styles of clothing spread across their wardrobe (like CLAMP characters), there’s always a few thematic elements that stay the same. Lists like these make it easier to just get the materials together and go for the new costume, instead of having to backtrack when all of your energy is focused on the upcoming project.