If you are a US Citizen getting a passport is far easier than you think. Start off with a simple trip online to the State Department website http://state.gov and head to the page that is all about travel.
You can either get a full passport for travel all over the world that is good for 5 to 10 years or you can get a passport card which will get you around in the northern western hemisphere for 5 years. Read up and decide which works best for you.
Generally for first time issuance you will need to get some documents together, fill out some forms you can download online, get your pictures taken – I usually go to Walgreens as they are fast and easy and cheap and then head to your local post office to get your paperwork verified. Check online for when you can do this- some locations have limited days they are open and you may need an appointment.
In a hurry? Read up on how you can get the process expedited either using over night mail services or going in person to a passport office near you. You will need to already have travel paid and booked to get things expedited in person- so make sure you read through what you need before you head out and wait in a long line.
Source: How do I get a passport?