While most people know they ought to prepare before going to a job interview, very few do it well, or take the time to do it thoroughly. Why is it so important, and how can you prepare better? Here are some observations and some ideas...
Where employers might have interviewed only 2 or 3 candidates in the past, employers now generally have an opportunity to interview a large number of potential candidates. In this competitive job market, they may be interviewing 5 to 10 candidates to find the one they think will be the best match.
In that large group of candidates, it's highly likely that at least one person will be well prepared, and be able to articulate their match to the job and knowledge of the organization better than the others. If you think it is likely that you will be competing against someone who has done their homework and practiced, be sure you do, too, so that you have a better chance to compete.
When it is clear that you went above and beyond the other candidates in doing your research, addressing questions well, and presenting yourself professionally, that is an indicator to the employer that you will likely perform well in the position as well.
Someone who takes the extra initiative to succeed in an interview, is also more likely to take extra initiative on the job. That's attractive to any employer.
While it's good to know what the company says about themselves on their own website, that's only the minimum amount of work. And it's what most candidates will do.
Take these extra steps to stand out from "most" candidates:
Most people do their preparation only by reviewing the organization's website and vaguely thinking about how they might address various questions that might arise. They think... "If I'm asked about _______, I'll talk about _______" without practicing specific answers. The result usually is that they ramble endlessly in their answers until they think they've covered it all.
While some people can speak pretty well "off the cuff," everyone will be much more effective if they write out their answers in advance and practice them. Writing out answers in advance causes you to put answers in complete sentences, and makes you articulate them more concisely. It's not necessary to memorize the answer word for word. However, the process of writing it out in the first place will enable you to articulate it much better. The vast majority of candidates never go to this effort. You will stand out if you do!
It's a competitive job market. Don't take the opportunity to interview for a position too lightly. Determine to be one of the few who will be well prepared and make the best impression, rather than one of the majority who fumble through!