Nobody knows your business as well as you do! You spend every day working in your field (we hope!) selling your particular brand of widget and interacting with vendors and clients. So it's likely that you have a detailed understanding of the most active topics and subject areas and where the most exciting new trends can be found in your line of work. This is a good thing - it's what brings you success.
In SEO, however, this specialized knowledge can be a handicap. We've found that our clients, even when they are great business people, tend to focus on trade language, insider topics, and those aspects of their business that are most relevant to them at the moment. They often neglect simple words and concepts more likely to appeal to the average consumer.
That's why research is so important - it helps you find out what actual consumers are looking for. Once you know the keywords and phrases being searched with the highest frequency, you can make sure you speak to your potential customers in a language they understand.
The first step in doing your keyword research is to come up with a list of words and phrases that relate to the thing you're offering or trying to sell. If you're selling used cars, you might include words like "used cars," "vehicles," "one owner," "low mileage," "economical," or "certified." If you're a veterinarian, you might want words like "vet," "dog," "cat," "animal hospital," or "pet care." If you're selling laxatives, well .... never mind.
You get the idea, right? The point is to come up with a healthy list of words related to your business. Get help from your employees. Ask your friends. Troll related websites. Take a few shots at it. When you have a list that seems fairly complete, go on to step 2: "Check Google Trends."