Focus on your industry - or on your area of interest and expertise.
Spend some of your valuable company research time investigating the needs and benefits of organizations in your industry that appear to offer the world. Do they specifically need people in your field? Or are they generalizing to, as they say, "cherry pick the workforce." You don't want to find yourself welcomed one day and then laid off six months later. If you can, talk to people who work there to determine whether it's a place you want to work, and if they would really appreciate your particular skills.
It is also helpful to find out the company history, financial stability, products and services, personnel, and perhaps some information about the company culture and how you will fit in; most companies, large and small, have web sites (see below) where they strut their best stuff.
Preparing for an interview is another reason to research employers. You'll want to know as much about your potential employer as possible. Standard interview questions are "what do you know about us" and "why do you want to work here." Research will enable you to have the right response - and the right questions, remember: "an interview is a dialogue."
Use your connections.If you have a connection that will help you find inside information, use it. Do you know someone who works there? Ask them if they can help. If you're a college grad ask your Career Office if they can give you a list of alumni who work there. Then call or email and ask for assistance.
Then use directories which will help you find those companies.
You can search Hoover's Online by company name or keyword. Big Book Yellow Pages allows you to search by business name, category or location. Vault and WetFeet offer job seekers an in-depth look inside some of the hottest industries. They also provide career advice and company and industry profiles profiles.
If you're interested in big business you can browse the Fortune 500 top companies list. Then take a look at the snapshot for company details, revenues and contact information. Fortune provides similar lists for the 100 Fastest Growing Companies and the 100 Best Companies to Work For.
Want to ace that interview?
Read anything and everything you can about that employer. Use Google to find the employer's web site. Then review the site to see what the company is saying about itself.
Next, take a look at what the rest of the world is saying; Vault Reports is a good resource to find specific, detailed information about a particular employer.