A costume is an entire project . Many factors will influence it and it could be or become a success or a total failure you're going to hate.I thought creating a guide will help some to learn something or be a reminder to other.Because at the end , we all want to succeed.
1- Know the colors that suit you the best.
We do not look great in every color of this world.Even if you like this flashy shade of pink , you may not look good with it.I personnally like grey but looks like sick when I wear it.Wearing color that suit you the best will make you look better,it's true for modern day cloth and stay true for costume.
2-Know your body
Depending of your shape , some clothing fit better , other don't and you don't like your image in the mirror.Same idea can be apply to costume.Some shape/cut/construction of costume won't make you slim and will look horribly fat.That doesn't mean you can't wear it , but do everything you can to look at your best by choosing a good color , fabric , underwear etc..
3-Don't make a project if :
a-you don't like it or have a lack of enthusiasm .
b- just to participate to a contest or a challenge.
c-not enough of budget to make what you really want to do.
d-do not have enough skills to complete it and will possibly be abandon.
4-Remember costuming is a hobby/pastime/fun activity.
Making sewing and creating a costume is something fun and it should stay this way.If things goes wrong and if you have difficulties , there is no shame if you ask for help.Don't wait until you want to cry before doing it.
5- Planification and organisation
A project is something you make step by step.Trying to skip step is no a good idea and do the step in the good order.For example , an historical dress.You should do your research before buying anything.You will scream if you did not buy enough fabric but will stay with 2m over if you buy too much.Organise your time and what you have to do.
6-Know your limits
Knowing your limit of budget and time is a necessity.Do not try to start something at the last minute and go to the bed at 2am.A big and long project required time .You can't escape that.Time can be an ennemi but don't let it become one.For the budget , remember you will have a plenty of other project.Do you really want and can buy this fabric at 25$ per yard or can choose a similar for 10$.Some people do not have budget limit but having one is not a bad idea.It's not a competition between you and someone else who's going to have the most expensive costume.Stay realist in your choice and let your feet stay on the ground.
I hope it will be of some help.Good luck if any project you have and I wish you it will be a success.