What I am going to share to you is how I prepare for it. Now, take heed, this is guaranteed not to work for everybody. It might just work on me but you might pick up a few tips and tools of trade. Just don't follow everything you read okay?
I'm sharing this so you guys what you'll have an idea. Some of these are basic and works for everybody the others are just quite unusual ^^;;
1. Pack before the event/shoot: I think this is very basic. Why do you need to pack a day before the shoot or event? Simple. Just to make sure you don't forget anything. I know some of us will just pack their stuff on the day itself but that leads to you for forgetting something to bring that is important to you cosplay like eyelash glue, wig cap etc, etc.. Also if you woke up late at least you won't be in a hurry in packing up ^^
2. Drink one can of beer or one bottle of Tanduay Ice (LOL) before the shoot/event: Okay not recommendable for everyone but I find it that it helps me relax when going to sleep and when I woke up, my skin feels so nice probably because I slept well XD. Minors don't try this.
4. Wear a part of your costume when commuting to the shooting venue or cosplay event: Normally, if your costume is not armor or not a gown, if it's possible, wear a part of your costume already in going to the event or to the venue of your shoot. It lessens your luggage and it makes dressing up easier. Normally, the parts of your costume you can wear are the one usually can blend in with your normal clothes, like the top, short or a skirt. Even the shoes if it's possible.
5. Go the event / venue in full make-up: If you're taking a cab or a car this will work but it is not advisable if you're using the MRT, jeep or bus. The pollution and heat will melt your make-up and you will just have to re-do instead of re-touching it.
So there you have it. That's what I usually do. How about you? How do you usually prep up for a cosplay?