Hey, fashion plate. What are you wearing to Comic-Con?
If you're packing jeans and shorts and t-shirts and that's about it - congratulations, you'll fit right in. See the random attendee sampling in the above photo. But that's most of us, not all of us. I know some of you want to look like you're on a red carpet and some of you just aren't sure about weather and dress codes.
First of all, be assured that no one will mock your outfit at SDCC. This isn't a cotillion. People tend to dress for comfort and as for those attendees in outrageous outfits, no one even blinks. This is an independent-thinking crowd. But if you're a first-timer, the below should help.
Nerdwear: Don't worry about being challenged to prove your knowledge about the gaming character or superhero on the shirt you're wearing. Someone may yell out a quote in a spirit of shared fandom, but you usually won't encounter one of those alpha nerds who like to make people feel inadequate about their nerd knowledge. And don't feel like you have to be deliberately obscure or go in the other direction and be trendy. Wear whatever you want.
Cosplay: Even if you love your costume and the way you look in it, bring alternate outfits just in case. You may get sick of being stopped to have your picture taken, or you might get hot and itchy. Or you could just sort of deteriorate and look less magnificent as the day goes on due to wig issues, broken weapons, etc. Experienced cosplayers know their limits, but new ones tend to want to change back into street clothes sooner than they think.
Formal wear: I used to shop for Comic-Con like it was the Super Femme Olympics, bringing an array of day and evening outfits, 6 pairs of heels, etc. Now I'm a lazy dresser because who cares? But if you lead the kind of fancy life where people might whisk you off to some kind of formal event, bring something - don't assume you'll have time to go shopping.
Shoes: Obviously bring something cushiony and comfortable. If you're really into flip-flops, be aware your toes may be stepped on when the Exhibit Hall gets crowded. If you don't have a pair of supportive shoes already, you'd better buy and break them in every day now. And bring moleskin, bandaids and maybe insoles. Talk to the nurses and servers in your life; they always know all the latest supportive footwear tricks.
Weather: As someone who gets cold easily, I find San Diego nights chilly. I always bring a hoodie and a sweater. If you're planning on spending the night outside, I would advise bringing something warm to wear, in addition to whatever blanket or sleeping bag you've got. If you're going to camp through the day and night, wear layers so you can bundle up at 4 a.m. and then peel it all off under an 11 a.m. sun.
Amount of clothes: Don't count on being able to do laundry. I know people who will bring two outfits and alternate them, but you have to realize how grimy Comic-Con can be. You're going to be brushing up against people, leaning against walls, sitting on grass, sitting in seats a sweaty person just sat in, hustling through the Gaslamp under a hot sun, and basically sullying yourself in incremental stages all day. I can't wait to shower the Con off before dinner and there's no way in hell I would wear the same thing that night. Maybe you're not that squeamish, but you'll definitely still want to make sure you have enough clothes.
Makeup and sunscreen: If heavy makeup is part of your cosplay - or you typically wear a full face everywhere - be aware that the Exhibit Hall can get humid and that the hustle between rooms, or between the convention center and the Gaslamp, can leave your face in a smeary mess. That goes double if you're wearing a hat, wig or any kind of headgear. What works in your air-conditioned office can be streaky and melted by noon at the Con. Consider bringing fixative sprays or a repair kit. Bring a good supply of sunscreen as well.
Backpacks and purses: You will need some type of bag to carry your extra phone battery, water bottle, sketchbook, charger, program guide, collapsible chair, lunch and so on. This is especially critical if your hotel is distant, since you won't be able to quickly go back to your room and then return.
Basically, the goal at Comic-Con is to endure. Vanity is beside the point. We all wind up looking rumpled and tired and no one cares. As long as you're comfortable and can meet whatever daytime or nocturnal opportunity arises, you'll be fine.