Be sure that everyone over the age of 16 has a state-issued photo ID!!! And keep it, along with your boarding pass, close at hand, as it will be checked at security screening, and perhaps again at the gate before boarding.
You will have to remove your shoes and put them in a bin, so wear slipons if possible. You will have to remove any jackets, sweaters, etc and place them in a bin. You will have to empty pockets and place the contents in a different, smaller bin. You will probably have to remove your belt. My husband puts his "stuff" in his carryon, then "dresses" after we are screened.
You will have to put your purse, briefcase, laptop, etc in a bin.
Ladies, you may or may not have to remove jewelry, earrings, barrettes(that one usually gets me) watches, etc depending upon the sensitivity setting. I had to be hand searched at one airport because my underwire bra set off the alarm.

It really depends upon the person doing the screening.
If you are travelling with a baby or small child, they will have to be taken out of a stroller, and will have to walk through, if possible. If you're carring a baby, you will most likely be stopped and hand screened. Any "loveys" will have to be put on the conveyor.
So yes, you may 2 or three bins going through x-ray before you're done. If I'm travelling with my husband AND son, I put the valuables in the middle bins, so that one family member will theoretically be at the end of the conveyor before they start coming through, and another will be at the end before they start moving.
Any toiletries in your carry-on must be travel-sized, and in a quart sized zip-loc baggie. I also put my make-up in a different baggie.
Make sure you check the TSA website to see the list of prohibited items.
Do not shoot a firearm within 24 hours of travelling, as the residue may still be on your hands, despite washing.
Do NOT, under any circumstances, get snippy/angry with the screeners!
As suggested, check both your airline and TSA website for further instructions.
I've found that being upfront with the screeners, and keeping my temper under control, helps the process. Go into it knowing you will be inconvenienced, and hope for the best. Or make it a game to see if you have a new reason to be searched (ala the bra incident) Also, there have been times when I KNEW I would be searched, so just went with the flow. (One time I was flying one way with no luggage; I had driven with my husband to a vacation condo in the mountains, but had to fly home suddenly, so left my stuff with him to bring home.) Then, I had to transport each of my parent's ashes, 4 years apart, so I knew I would have extra scutiny.
Also, check with friends and neighbors, or on the net, about how early you should arrive at YOUR particular airport. Mine is small, and easy to get to and through, so being at the airport 2 hours early may be a waste of time...
depending upon the flight time.
I live 20 minutes away during non-peak times, so if I leave home 2 hours before my flight, I still have plenty of time. I leave 2 hrs & 45 mins earlier during rush hour.
We once had to catch a flight out of Logan, in Boston, and arrived 4 hours early; we almost missed the flight, and this was BEFORE 9-11! We had planned on having a leisurely lunch, but instead had to grab a snack in the concourse.