The hardest part about making sure you're ready for a con in time is making the final decisions about what you want to cosplay and what you need to make it happen!!
*My suggestion is to have a final list of what you need to buy for your cosplays 4 months before the con!*
Here's what you should try to list up:
1. what you will be cosplaying, and which day of the convention you will wear it
2. an itemized list of what you need for each cosplay, including costs
3. which items will take the longest to make/come in (CHECK SHIPPING TIMES!)
4. where you will buy things from (links!)
5. when you need to order each thing by
Then, you can order things before the dates that you need to order by arrive, and you won't have to pay expedited shipping at the last minute!
Example: My Final List for Katsucon 2016
1. What & When
Thursday: Tifa + Nozomi in PJs!
Friday: Purple Sparkle Dress Nozomi + Kitty AKB0048 Mimori
Saturday: Fairytale Nozomi
Sunday: Casual Nozomi!
I'm still considering whether or not I will get a certain cosplay that many of my friends are wearing, but I'll decide that later ^^
2. Itemized Lists for Each Cosplay + Costs
Please, nobody add them up. I know what it all costs. Trust me, I know. My wallet already feels the pain hahahaha.
3. Which Items Will Take the Longest
For me, the cosplays that will take the longest are all the Nozomi ones, because I'm ordering them from Taobao and shipping can take a while! The shipping time can be just a few days, but I also have to account for manufacturing times, so I'll want to order these at least 3 months in advance to give enough time for any problems.
4. Where You Will Buy Things From
Things I don't need to order:
Tifa - undecided (yikessss)
Kitty AKB - @angelipon is making it for me!!! <3 <3 <3
Things I need to order:
PJs Nozomi - Taobao seller, here
Purple Dress Nozomi - Taobao seller, here
Fairytale Nozomi - Taobao seller, here
Nozomi wig #1 (for fairytale)
Nozomi wig #2 (for all others)
5. When Need to Order By?
Realistically, I can wait until the beginning of December to order because Katsucon isn't until mid-February, but I plan to order before the end of October so I have plenty of time to make sure nothing is missing!