If you know you're going to the convention ahead of time, it's best to pre-register. Most conventions allow attendees to purchase a registration badge months in advance at a discounted rate by either paying electronically through their official website or mailing in a check with the registration form. This can save you from what can be very long lines at the registration desk. After your registration has been confirmed, you only have to wait until the convention day to pick up your badge at the registration desk. Remember to bring a photo ID when picking up your badge.
If you don't live near the convention center it's best to book a hotel room nearby. Often there is a hotel attached to the center that will give you a better deal if you let them know that you are booking a room in order to attend the convention. Try to book with friends as well, as this will drastically cut down the cost.
Costume play, or cosplay, is the common practice of convention attendees dressing up like their favorite anime characters. If you are planning to make your own costume, don't wait until the last minute to do it. Crafting your outfit can be time consuming and it has to be has "right" as possible to the character. Remember the other attendees are well-educated in this field and will judge you by your looks.
It is also possible to buy professionally made costumes from websites such as QQCosplay (see resources). If you are interested in other people's cosplay as well, remember to bring your camera. Bring along extra batteries, an extra roll of film or memory card so you don't miss any photo opportunities.
An anime convention bonus is the chance to meet guests, namely artists, directors, and voice actors, who work in the industry. Most will have guest panels throughout the convention in which fans can ask questions, and autograph sessions if you have merchandise to be signed. Check the conventions rules online to see how many items you are allowed to have the guest sign. The guests will sign most things you bring them, from manga to DVDs to figurines, but by no means should you bring a bootleg copy of a movie or comic _ this is illegal, stolen material, and could be insulting to the guest.
Even after paying for registration and your hotel room, you'll still need extra cash. If you have any money left over after food and other necessities, you might want to check out the dealer's room. You can expect to find good deals on manga and anime, so this is a wonderful opportunity to beef up your collection. If you want to buy other merchandise you should check out various stores online ahead of time such as Anime Castle or Right Stuf (See resources) to see how much items generally cost so you don't get ripped off.