Cosplay is not Consent.
This is so important to remember, whether you're a veteran congoer or just getting into going to conventions.
Even as cosplayers we sometimes forget to ask each other things like: "May I take your picture?" "Is it okay if we pose together?" "May I touch you/your prop/your cosplay?".
Not everyone wants pictures, to be dragged into a group, or even to be touched. Even if we are all nerds and a lot of normal social barriers have been taken down, we need to respect people and personal boundaries.
Along with our hands, we need to remember to be respectful of our voices and actions. Not everyone is going to try and act in character and no one should ever be forced to. Unless the cosplayer is asking for advice, never tell someone that there is something "wrong" with their cosplay.
This also applies to comparing cosplayers. Everyone has a different budget/skill level. This is a fun hobby.
Never use derogatory, hurtful, or racist language. Even if it's "in character" this is never okay and will probably make other people uncomfortable. Be respectful.
Some rules of courtesy are: If a cosplayer is eating, sitting, or obviously taking a break DO NOT ask for a picture or interrupt them. If you see someone who is new or maybe a family member that's not part of the community or is a parent with their kid that is part of the community, remind them gently to ALWAYS ask before taking pictures of ANYONE.
If a cosplayer is being photographed with what looks like a professional photographer do not interrupt for a picture or join in to take a picture. The cosplayer is probably paying money for the shoot and sometimes it's charged by the amount of time spent.
At any point you feel in danger or see another cosplayer being harassed, Go get Con staff immediately.
At the end of the day, we're all nerds and at conventions to have fun. do your best to make the environment open and welcoming for everyone.