Programming and cosplay have 2 things in common: your time estimates are usually crap. How I plan my cosplay projects TrelloCheck out my planning board for my Rufio Cosplay you can even copy the board and use it as a template guide. When you are working on a large cosplay projects it's easy to get overwhelmed. That is why I break down every part I need for the cosplay, in advance. I also tend to over-engineer my projects, I went through scene by scene in Hook to get front and back shots of battle Rufio, and count all the bones, I actually thoroughly enjoy breaking down the pieces, it's therapeutic!
Hope this helps you finish those awesome cosplay on your wish list!