These are by no means hard written rules but they are rules that I (loosely) follow to have a good time at a convention while not upsetting anyone in the process. The most important thing is enjoy your day(s) at the convention as well as be considerate of others.
TL;DR Don't be a prick.
Photo by Aperture Alternative
As an attendee
Always ask for permission before taking photos and move on if you are declined.
Ask yourselves a few questions; do they look like they're in a rush? Are they resting/eating? Do they look exhausted? If you answer yes to any of these questions, it's better not to bother them and come back later.
Looky looky no touchy
Normal people hate it... cosplayers hate it even more! Just imagine going to a strip club. You touch the strippers without permission, you get thrown out. If you do get a chance to handle other people's props or costumes, be very careful and follow their instructions at all times.
There are many dos and don'ts which may scare a lot of people from interacting with cosplayers. Something I would encourage people do more is to chat to the cosplayers about the costumes and share the passion and interest.
Striking up a topical conversation is great but don't get too carried away. Recognise there are others who also want to speak with the cosplayer, or the cosplayer themselves have something else to do since after all, they're here to enjoy the convention too, so keep conversations short and sweet.
Cosplayers are people too
Cosplayers may be in character but they are not the character. Exchanging friendly character referenced banter is great but do keep it friendly and non-personal.
Clear up your litter!
This applies to outside conventions as well. Pretty self explanatory. Leave the place how you would like to have found it.
Don't be creepy
There are many definitions of creepy, and sometimes it may be ambiguous. Let's use an example, imagine if the cosplayer in front of you is a young child, would you do the same things to the child you're about to do? If yes and if you're not prohibited to be near schools by law, then carry on.
See a creeper?
Note it down and alert security. That person who you see being harassed may be you one day! Respect people's personal space.
Speaking of personal space, if you are not able to get through a narrow gap, a simple "excuse me" goes a long way. Cosplayers spend more than they'd like to admit on creating costumes that everyone can enjoy. A lot of the costumes and props are fragile and may break on impact.
Do note that some "creepy" behavior may be due to a disorder or disability!
Walkways are called walkways for a reason. They're not standways, so please refrain from congregating in the middle of paths.
Keep track of your drinks
It's great to have a few drinks throughout the day, however if you can't handle your drinks, refrain from drinking one too many. 90% of the other attendees are sober during the day of the convention.
For the boys
There is a time and a place to admire people's costume. At the urinals is not the time or the place. Keep your eyes forward and stop checking me out. Even though we both know you're looking at my costume and probably laughing internally at my struggles to pee, it still makes me very uncomfortable that you're watching me pee.
As a Cosplayer
Grin and bare it
Cosplaying a well known character which only has a handful of recognizable quotes? Be prepared to have those phrases shouted at you every few steps. It's fun at first but gets stale very quickly. It may be stale and annoying for you but it's still someone else's first time seeing it and it's still funny for them. This is one of the biggest down sides for me from cosplaying a well known character.
H8trz gon' h8. Potatoes gon' potate!
Not everyone holds the same mentality as you may do. Some people are born to be a assholes. If you get comments walking to and from conventions, either humour them or ignore them and carry on.
Travelling to/from conventions
You may get asked all sorts of weird and wonderful questions from that curious kid in the pram to their mother, to the rowdy drunk party on the train. Some may be polite, some may even shout abuse at you from across the road. The best thing to do is just to carry on and not encourage them.
Know your limits
Keep yourself hydrated and fed to avoid from being "hangry". I learnt it the hard way. I've been to a convention, got smashed and caught the last train back. I was literally recreating the delete scene from Iron Man 2
BRING SOME BODY SPRAY.
You sweat, you smell.
For the boys
If you're a guy, nobody wants to see your yogurt slinger that's hiding under that spandex suit. Yes, I am referring to your penis. Wear a dance belt.
This is extremely important with large costumes. Make sure you know how wide you are before charging through gaps and crowd! Sometimes people aren't touching your costume, you're touching them!
Don't be judgmental
Everyone has worked extremely hard on their creations. Not all people has the same resources or experience has you may have. Keep your negative opinions to yourself. Focus on the positive aspects of the costumes. My mother always taught me, if you have nothing nice to say, better to say nothing at all. Advice for people are great but only give them if they asked for it.
If you run into someone with the same costume as you, give them a hi5 for sharing the same interest/enthusiasm as you do. After all, people attend these events for fun!
Being in character
This can be fun at times but if you're taking it too seriously, it may get a bit weird for general attendees. There's nothing wrong with replying to a few questions in character but try not to get sucked too deep.
Keep track of your drinks
This applies to cosplayers too! It's great to have a few drinks throughout the day to loosen up, however, if you can't handle your drinks, refrain from drinking one too many. This is a family event after all! You are meant to be a role model, not rolling on the floor!