Traveling and flying for the first time and I could use some help/tips

Well.. not sure in what extent this is meant to be serious, but here we go...
It'd be more helpful if you give us more deets. What place are you going to visit? Some place with a similar culture, which will be more easy, or something more exotic?
Are you afraid of flying? If not, it's simple. Pack the things you need, get to the airport, check in, seat, fly, profit.

I'm not familiar with american airlines, but there are guidlines that you can easily access in the internet. There are certain regularities about liquids etc., too, all of which you can find in the internetz in detail.

I think you'll do just fine in NY and Philly. Have fun at the SF meetup!

Lay out all the stuff you plan to bring on your bed. Take half.

General baggage tips -

http://www.aa.com/i18n/travelInformation/travelTips/tips_baggage.jsp

Carry-on restrictions -

http://www.aa.com/i18n/travelInformation/baggage/carryOnAllowance.jsp

Experienced travelers such as myself do everything we can to avoid checking baggage as its a pain to deal with and will slow you down. This may not be possible for you as you're going to be packing heavy as a first time traveler. Just ask yourself this as to every item - "Am I sure I need this? How many times will I use it? Is it at all possible to use something similar once I arrive?"

Depending on how long the travel time is, I'll pack a book or multiple books. As for clothing, I pack stuff I can wear a couple of times: wool, denim, chambray, synthetics. Beware taking colognes - take small decants instead of full bottles, and you pretty well have to check a razor if you bring one.

whenever I fly in to JFK or LGA, I take a cab from the airport to wherever. It's usually $30ish from LGA and $45 from JFK. It's too much of a pain any other way and saving $20-25 bucks is not worth having to deal with the forever time it takes with the other methods of transportation plus having to get from Midtown to home via taxi or subway.

also, you flying from NYC to Philly?

What sort of razors are you talking about? Disposable razors are fine, I have them in my carry-on on every trip.

give yourself plenty of time - they used to say 2 hrs international, 1 hr domestic, but stay on the safe side and give yourself 2 hrs for your first domestic flight, just in case. American airports are horrible places to be in. It's pretty self explanatory from curbside to boarding - you walk into airport, you redeem your boarding pass via ticket reservation number at desk or preferably self check-in machine, everybody cattle herds through a TSA security checkpoint bottleneck, and then you find the gate listed on your pass, and you wait til they call your boarding group.

Wear comfortable but respectable clothing. Expect to have to take off your shoes, your belt, and everything out of your pockets, as well as anything metal off your body for the TSA scan, so expect that and don't carry more than you need. If you need to carry suspicious shit like medicine, carry it in prescription labeled bottles, and in ziploc bags away from your other stuff. Try not to make a tangle of your electronic stuff because you gotta take that out for the scan as well. On the bright side, you can carry a bomb through a TSA checkpoint and it's likely they will miss it in the scanner because they are too busy challenging people on their shampoo and conditioner.

Pro tip, seriously, if you are nervous about this - either call AA on the phone now and see if you can upgrade to first class or business class, or get to the airport early, check in on the e-ticket machine with your credit card and AA ticket number, and they give you the option to bump up classes. It's $90 or 115, can't remember, and most AA domestic flights are short, but still, to not have to line up with the angry people in coach, and going through priority TSA and priority boarding, getting a drink or two on board so that you can sit back and enjoy your flight - that is priceless sometimes. $90 is not a lot in the world of air travel nowadays. Seriously, upgrade for the extra cost, tell them it's your first time flying and that you want a little special treatment - they will give it to you and you will feel much better. It's their job to make sure you're 100% safe and reasonably satisfied.

take the Apex bus (or Eastern travel) from NYC to Philly Arch St. Its pick up is on Allen St in NY and it drops you off in the middle of Philly. Pre-order a ticket for ease, they're like $10 or $12 one way.