With over 4,000 colleges and universities in the US alone, the college search process can be overwhelming. I generally recommend that students start the process of building their "long list" - a list of all colleges and universities they are interested in - as early as possible during their high school experience. During freshmen, sophomore, and junior years, you should keep a list of all colleges that spark your interest - don't worry about specifics now, you're casting a wide net to capture all possible colleges that could turn out to be your dream school. Towards the end of your junior year, you'll start sorting and narrowing down to get the list of colleges you will ultimately apply to.
But with so many options, where do you start? The following tools can be helpful in generating your long list:
College Board: Search nearly 4,000 colleges and universities according to parameters you can set, including location, type of school, majors offered, support services offered, athletic opportunities, cost and average financial need met, and more. For each college, there is a profile that includes a brief overview, application deadlines, majors and learning environment, campus life, application process, and cost and financial aid information. I like this site because it's user-friendly and includes a lot of information in a consistent format - the profiles for all colleges are organized in the same way, so information is easy to find. On each college profile, in the menu bar to the left is also a "see similar colleges" tab, which can help you find new schools you may not have thought of. If you have an account, you can save your college list. The college board website also has a wealth of other resources, including information on majors and a scholarship search.
College Greenlight: You need to sign up for a free account. After entering some basic information about yourself, you can search colleges based on your interests. Based on the colleges you choose, the site will suggest similar colleges you may be interested in. You will also receive messages (within the site, not to your email) from colleges interested in students like you, which can give you some new ideas of colleges you may not have known about. There is a tool to compare colleges, and College Greenlight also provides information about college majors and has a scholarship search tool.
CollegeXpress: Again, you will need to sign up for an account (it's free). The site offers a college search tool, where you can search based on location, majors, sports and activities, size, etc. There is also a scholarship search tool. My favorite thing about this site, however, is the "lists and rankings". These are not your US News and World Report generic rankings, these are lists created based on very specific factors - you can look at lists of the best schools for a certain major, but also by sport, and by factors such as "Colleges for the Independent Learner" or "Colleges for Students Slow to Make Friends". The lists can be useful in finding colleges of interest, of course, but they can also help you figure out what's important to you in your college experience - including some things you may not have thought about before - like "Schools with Lots of Cooperative Education Options."
And for when you're a little farther along in your search, and are looking to compare colleges based on affordability and college outcomes:
The Chronicle of Higher Education: College Completion: This website allows you to compare colleges based on a variety of factors, including freshman retention and graduation rates (both 4- and 6-year). This is useful because many websites only give 6-year graduation rates. The information on this site allows you to see the percentage of students who graduate in 4 years, which is important because graduating in 4 instead of 6 years will obviously save a lot of money - two full years of colleges expenses.
College Scorecard: This site lets you filter by degree type, major, location and other factors, and compares colleges based on average annual cost, graduation rate, and average salary of graduates. If you click on a particular college, it provides more information, including a breakdown of average cost for different levels of family income, average debt of graduates, and more information about the school.
And to help pay for college:
Raise.me: Sign up for a free account, and earn microscholarships at over 250 participating colleges. Students document achievements (good grades, extracurricular activities, taking the PSAT or SAT, taking an AP test, community service) to earn microscholarships from participating colleges and universities. If you end up attending one of those schools, the money earned will be awarded through your financial aid office.
Taking some time during the first three years of high school to research colleges and create a college list will save you a lot of stress and frustration senior year.