Call the airline ahead of time to ask how far in advance you should arrive for your flight. While an hour and a half is generally recommended for most flights, larger airports and/or airlines might recommend that you arrive even earlier. If you are traveling a great distance to the airport, check traffic reports before you leave the house, and plan your route accordingly. You should also call the airline before you leave the house to inquire about any delays or changes to your flight time.
Finish packing the night before, in order to avoid any last-minute delays. Make a list of everything you will need for your flight, and pack these items in your carry-on bag. Call the airline ahead of time to inquire about any size restrictions for carry-on luggage. Make a separate list of items you will need over the duration of your trip, and pack these items in luggage to be checked. Pack all luggage in a way that allows easy access to the items within, and be aware that your luggage might be searched in a public venue.
If your flight has layovers, contact the layover airports ahead of time for an estimated distance between connecting terminals, or look online for a general layout of the airport. If your layover time is substantial, take the time to map out a few food venues, newsstands, and any other points of interest in and around the airport. Do not, however, stray too far from the airport itself, for risk of missing your connecting flight. In fact, it is probably best not to leave the airport at all, in order to keep tabs on potential flight updates.
Arrange for transportation to and from the airport ahead of time. If you are using a taxi or shuttle service, ask to be picked up at a designated time, and contact the service immediately if your travel plans change. If a friend, family member or colleague is planning to pick you up at the end of your flight, keep them informed of any changes in travel plans as well.