You will see many, many posts detailing how to do specific things. These are all amazing, but firstly please know that there is no ‘correct order’ to making a costume. There isn’t a pamphlet that describes it, you just have to start and then learn tricks as you go.
That said, listen to those professional cosplayers whose life and soul is their work. They know everything under the sun, and watching a couple videos to get an idea of how to do something is great. But don’t expect your first try to look like their product. They do this for a living, and you’re just starting. Cut yourself some slack – after all, this is what professional movie costumers do all the time and they’ve had years to get up to scratch. I know it’s not great to hear that your first cosplay won’t be amazing but it probably won’t be. At least, not in comparison to your later ones, should you continue.
Don’t be afraid of picking something hard to start with. That’s how you learn, and anyway, the point of this is to have fun, and to like the final product. You won’t like it as much if you settled for a character or idea that you don’t like that much just because it’s simple. Go for that overdramatic character design, and be proud of the result.
If you’re going to a con and plan to let people take pictures (because they will ask, no matter your level of cosplay. Or at least, there is a strong possibility) figure out a pose. Stand in front of a mirror, have a friend judge, or use a phone on timer, whatever you need, but have a pose that you know looks good. If you’re confident about how you portray the character you’ll feel much more comfortable, especially if there is a photoshoot for that game/anime/show and everyoe expects you to pose.
Do not pay a fortune for fabric. If you can, secondhand stores are your freinds. I made two cosplays out of a super long maxi skirt, with other skirt parts of different colours (and some spraypaint, but moving on). One of my better cosplays so far cost a total of about $20, exluding the wig. While this sounds expensive, it’s way less than many pay for supplies. So: scrounge all the extra fabric you can get.
IF WORKING WITH VELVET HOWEVER, make sure the velvet isn’t coming apart. Velvet in fabric stores often sells cheaply because velvet ages. Badly. It will fray and fall apart in your hands one you try sewing with it – you won’t notice at first but it will often come apart around the seams (it can be worse and just fall apart, but they probably won’t sell that). So just … be careful. Ironically the secondhand sort-of velvet stuff that you will find as shirts and shirts and such, very cheaply, is often sturdier.
Put hidden pockets in your costume or try and have a matching bag. It’s not needed, but it looks more cohesive than Weiss Schnee with a red sports bag, for example. You can always just add an extra layer of fabric around a bag, to remove afterwards, and painting a bag to match is also great, if you don’t mind doing it to the bag.
If you can, use setting spray or powder on your makeup, if you are wearing makeup. You will touch your face, or it will flake, and you might forgett to touch it up, and this makes it easier to do an entire day in cosplay regardless.
Take extra saftey pins and bobbypins and glue and string (and fabric pens in the colour of your fabric) if you can, and ESPECIALLY if you haven’t had a chance to test the cosplay before wearing it to an event. Things will come up, and you will want to fix them.
If you’re like me and wearing a short, flimsy skirt …. weight it. Sew small pebbles into the inside in pockets or something. It makes you less awkward when there’s a wind, and everyone else is posing dramatically and you’re clutching your clothes.
Boot covers are your freinds. If you have a pair of boots roughly the size of many characters’, then you should be fine – just make a covering for them, so you don’t have to get new boots or something.
Fairy wings – melted cellophane. But make sure it’s reallly melted at the seams or else it comes apart, albeit slowly.
Expect weird looks from passers by if going to a con and the con is not common knowledge.
Try and go with a freind!! It makes things more fun and you more comfortable if you need to take a break.