Cons cost money, and if you're planning to barely scrape by at a convention, don't plan to go. Budget around $600 for each convention you plan to attend ($300 for a plane ticket, $100+ for a share of a hotel room, $100 for food, and $100 for incidental expenses that inevitably come up.) You should plan ahead by having at least $100 in your wallet in $5's so you won't have trouble at a con running around to find change.
Preregister. When you preregister, you will save a few bucks off the cost of registration, but more importantly, registration tables usually have fastlanes for preregistered attendees and/or sponsors. The less time you're waiting in a registration line, the more time you're having fun!
Reserve your room early. It doesn't cost a thing to reserve a room, all you have to do is put a valid credit card on the reservation, which will not be charged until you arrive, or cancel at least three days before the convention. There's nothing worse than being several blocks away from all the action. Be sure to register for the rewards program of the convention hotel (free to do online), and enter your rewards number when you book your room. You'll earn points for your stay at the con that may come in handy someday for freebees.
Book your plane ticket at least 90 days before the convention. This will get you the best discount rates. You may use Orbitz or Travelocity to find the cheapest flights to the con, but once you identify a flight that works for you, book it directly through the airline's website. The base ticket cost will be the same, and you'll avoid the $5-$10 booking fees the big travel websites tack onto the plane ticket price. Be sure to register for the frequent flyer program of the airline you'll be flying (fast and free to do online), and enter your frequent flyer number when you book your ticket. If you've already booked your ticket, you can call the airline reservations line anytime before the day of your departure to add it to your ticket to get your miles. Maybe you'll never accrue enough airline miles to get a free ticket, but you can often trade them in for coupons, free magazine subscriptions, or other goodies.
Check in to your airline online 24 hours before your departure and print off your boarding passes to avoid waiting in any airline desk lines when you get to the airport. Keep all your boarding passes, hotel confirmation numbers, frequent flyer numbers, convention registration confirmation papers in a folder in your backpack.
Pack light. You want to avoid checking baggage at the airport because checking baggage will require additional time at check-in and will require you to navigate an unfamiliar airport at your destination to find your bag. Most airlines will let you pack a small carry-on bag to store in an overhead bin and one small personal item, such as a backpack, purse, or laptop computer bag to put underneath the seat in front of you. Backpacks make excellent personal items because they are easy to carry around. Your carry-on bag should be a small duffle bag that meets your airline's size restrictions. Avoid bringing a rollerboard (a small suitcase with wheels) as these take up quite a bit of space in the overhead bins, and since many other passengers fill up overhead space with their own rollerboards, you may end up checking your rollerboard when you board.
Pack all your clothing, toiletries, and other items you will not need until after you arrive in the con into your carry-on bag to be stowed in the overhad bin, and pack any items you may need to access during the flight into your small personal item. Try not to bring a laptop; they're heavy, take additional space, and probably won't be used much at a con anyway.
Arrive at the airport about two hours before your scheduled flight. Flights typically board 30 to 45 minutes prior to the departure time on your ticket, and you want to allow yourself ample time to check in, get through security, and find your gate.
Dress for the airport. Do not wear large belts or clothing with metal rings or chains. Once you arrive at the airport, place your cell phone, keys, and loose change into your carry on bags until you get to your gate. Having nothing in your pockets except for your wallet/ID and your boarding pass will decrease your chances of having to walk through the metal detector multiple times or worse, being taken to a separate area to be wanded or searched, which can delay and frustrate you. Also, do not wear coats or heavy jackets, as you will probably get toasty on the airplane, but will not have anywhere to stow your coat or jacket once all the overhead bins are aboard.