Tip #2: Network in the Convention Community. There are plenty of online communities for conventions where you can connect with other cosplayers and photographers. Do a search for a show you want to attend through Facebook and see what's going on. Many shows have group gathering photo shoots organized by attendees. They sometimes
include special guests such as comic creators or actors. Photographers sometimes set up a booth or have a meeting place at a show where they offer sessions with cosplayers.
Tip #3: Buy a Professional Camera. It costs a pretty penny but it's worth it. If you own a professional camera then you can take high quality photos at your will. You can use a tripod or have someone you know and trust operate the camera for you. If you can't afford one, purchase the highest quality point and shoot camera available on the market. I've had photos taken with a point and shoot camera such as my Red Riding Hood collection that I'm pleased with. I would also advise in investing in some sort of Photo Shop program. You never know what you can accomplish while experimenting with the program. It also comes in handy when you have to do something quick and easy like removing a blemish.
I hope you found my quick guide helpful. Have fun and Happy Cosplaying!