For a cosplay with lots of small details, I find that what helps most it to really break it down into its component parts before starting.You can do this in several ways, or combine ways.
One way is to draw everything out. Make a quick sketch of the character and outfit and make sure that you copy every single detail over from the art. This way, you are forced to think about what each item is and where it belongs. This can be especially useful in some outfits where things like attachment points are ambiguous, or where there might be partially-hidden details.
Another way to go about this is to label a reference image. I like to print out images and do this by hand, though you can do it digitally as well. Draw an arrow to each piece and label what it is, what the color is, and what material you think it is. If you have ideas on how to make the items, you can write that down, as well.
You can also make a list of all the items, which is helpful once you’ve broken it all down visually. Some people also make collages of different reference images so that they can see the items from different angles. It might also be helpful to compile tutorial or purchase links in with your collages or lists, if that seems useful.
As for actually tackling the details, do it one part at a time. Give yourself plenty of time to work on the costume, and take it slowly if you have to. It helps to see things not as a daunting whole, but as small parts – for example, not a large and complex garment, but a set of sleeves, and a torso, and some embroidery on the sleeves, and this trim sewn to the neck, and that trim sewn to the center front, etc.– so that you know that you can tackle the costume one piece at a time. I find that making detailed to-do lists helps with this, and the more I break down the steps, the more it helps (and the more satisfying it is when I work on the costume for an hour and can check off 3 things from the list!). Don’t think of it as “I need to make Mei’s prop,” but instead take it slowly and think “I need to make this one specific part of Mei’s prop.” It may seem daunting to look at that long list of things to do, but even then, you can break it down further and only make a list for the prop, or only for the top, etc., as you go.
It also helps to take a break, even if it’s just taking a break from one part to work on another part. Sewing can happen while paint is drying, for example. Looking at things with fresh eyes can also help if you start to become frustrated with a piece.
I hope that helps! Good luck :]
—Fabrickind / Q&A Staff