Do the online checkin and print out your boarding pass. You should also check to see that you have a good seat - you can change it if the plane is not sold out.

Get dropped off at the designated terminal for your airline (or the designated area if a small airport).

If you do not need to check a bag, you can proceed straight to the gate. There will be video screens as you enter that will list the gate by reference to your flight number. It will also be on your boarding card, but check the screen as it may have changed. This screen will also note if there are any delays.

If you do need to check a bag, use the check in kiosk that will be located near where you entered, and hand the bag to the clerk behind the counter. Routine varies by airport, but they will probably have a designated line for this.

Follow the signs to your gate. You will have to go through TSA screening. As someone else noted, follow the new restrictions on liquids. (3oz or less bottles, all in one small baggie.) Have your boarding pass and ID (drivers license typically) ready to show.

You'll need to take off your shoes, take out your laptop and your liquid baggie.

Head off to your gate and await your flight. You will not need to check in again at the gate. You'll just need to show your boarding pass to get on the plane.

Don't stress, it is all well marked!