The first step is to visit the website of the state you want to take the exam in to make sure that you're eligible and to check your deadine for registering to take the exam. The same exam is given in all states, but the eligibility criteria change from state to state. You may pass the FE and PE exams in different states.
Eligibility You need to have an ABET accredited undergraduate engineering degree, or be a senior currently enrolled in such a program. An ABET accredited engineering technology degree will not pass muster in most states. There is one ABET-accredited masters degree in one of the Dakotas.
If you acquired your engineering degree outside of the US, the Washington Accord may help you out in some states, but other states may ignore it. If the Washington Accord doesn't cover you, then you need to pay a lot of money to ABET's Engineering Credentials Evaluation International (ECEI) and be very patient. If your undergraduate degree exactly matches the ABET equivalency requirements (including humanities courses) then you're okay. If not, you will need to make up these deficiencies before you'll be allowed to take the FE exam.
Preparation The NCEES website has a wealth of information and a book store that sells review materials.
Senior in an accredited program If you're taking the exam as a senior, you're best-placed to do well in the exam, providing that you put a little effort into studying for it. If you don't pass as a senior, many colleges won't let you graduate. Taking the test after being out of college for a while is a very difficult undertaking, so take it and pass it. If you buy a preparation guide (or your Frat or Sorority has one) you shouldn't need more than a couple weekends to get up to passing speed. You probably want to take the discipline-specific afternoon section.
Recent college graduate It'll have been years since you've seen much of the material, so allow yourself 50-100 study hours to get to grips with it again. You will not have used most of the material in your daily working life, but it shouldn't take you long to get back into it. It's up to the individual whether to take the general or discipline-specific afternoon section.
Graduated more than five years ago There will be a lot of material in the test that you haven't seen for nearly or more than a decade. Allow 100-200 study hours to prepare (3 months of 2 hours a day). The general test is your friend as you will need to spend significant time reviewing the material for the morning session and there's no point in spending time reviewing new material for the afternoon session. If you know some sections very well, you can probably get away with leaving out other sections (focused study).
Preparation tactics Many private institutions offer video or formal review classes. These are generally expensive and time-consuming, but useful if you're not good at teaching yourself. Forming a study group is an excellent idea as it helps you stay on-track with your review timetable.
There are many brands of review material; some include the theory and worked example problems, others are just example problems with worked solutions. The NCEES bookstore sells one brand of review material. Professional Publications Inc. is another trusted brand. From time-to-time you can get review material from eBay for a steal, but be very careful to check the date on the book. Don't save five bucks buying a five-year-old book!
Always study with only the FE Supplied-Reference Handbook as a reference, as it's all you're allowed during the exam and it pays to be familiar with it. Don't pay for the reference book, download it free off the NCEES website.
It also pays to prepare with the calculator you'll be using. There are only a handful of approved calculators and most of them cost less than $15 at Wal-Mart. If you arrive at the exam site with a non-approved calculator, it will be taken away from you and you will have to take the test without a calculator.
Taking the exam The exam is an 8-hour marathon. Get enough sleep the night before. If you must travel to the exam site, get a hotel room the night before.
The morning session is easy, but the afternoon session is difficult. Fortunately, you only need a combined score that passes, not a passing grade in each session. The pass mark is 70%, but usually that's a raw-score of 49%. The exam is multiple choice (4-options) and there is no negative marking. Give each question a go, and then guess if you still can't get to the answer.
You are only allowed to bring a clear bag into the exam room. No paper is allowed. You may (and should) bring food and water, tissues, a warm sweater, a spare calculator, earplugs, etc. Cellphones, PDAs, disallowed calculators, etc. will be taken from you before you enter the exam room, so leave them in the car.
Supervised bathroom breaks are permitted.
Do not, under any circumstances, write in the NCEES Supplied-Reference Handbook. After the morning session, they will remove any pages you have written on.
Pace yourself. If a problem is taking too long to answer, skip it and come back to it if you have time. Answer the problems you know best first to avoid careless mistakes as you get worn out towards the end of the 4-hour period. A five-minute break with your eyes closed and your head on your desk midway through the afternoon session will do wonders for your accuracy.
If you've prepared to take the general test in the afternoon, the morning session should be very easy and you should finish early, which will give you a longer lunch break to recover. You will have to leave the building during the lunch break, so dress appropriately for the weather outside.