To work for comic conventions, you could start by networking with people in the industry. Attend smaller local events and make connections. Also, build a portfolio showcasing your relevant skills, such as customer service or organizational skills. Volunteer at conventions to gain experience and get noticed by the organizers.
Well, winning at comic conventions can involve several things. First, do your homework and know the event schedule and special activities. Then, prepare unique and high-quality merchandise or art if you're selling. And don't forget to network and build connections with fellow comic enthusiasts and industry professionals.
It's hard to give an exact number as new ones pop up all the time and some might not be well-publicized. But there are quite a few major ones around the world each year.
To make a living at comic conventions, you could become a popular cosplayer and get paid for appearances. Or, if you're a writer, sell signed copies of your comics or novels. Additionally, providing comic restoration services can be a profitable option.