In-house counsel is not your typical job. You're a lawyer, but you're not working at a law firm: you're at a company that's focused on something else. In a way, you'll be both an insider and an outsider.
If that is exactly the job you want, how will you bridge that gap and show the interviewer you're the right person for the position? In Johnny Cochran's words, "preparation, preparation, preparation." And you might get some insights about yourself too.
Research the Industry
If you're going to be working in this industry, you need to know it and be excited about it. Or at least excited enough to shed your life's blood working in it. The Internet is one place to start your research -- and don't forget to check out Melissa Peter's great post on that subject -- but also consider reading a good memoir written by an industry leader. It will give you a feel for the industry, much more so than dry facts siphoned from Google. It could also be a fun topic of conversation during your interview, and the fact you actually read a book demonstrates your enthusiasm.
Research the Company
Research with a purpose. What does the interviewer want to see? She probably doesn't care if you know the names of all the board members, but she'll definitely like to know that her company isn't just another one on your long list. She wants to see that you want this job, not just a job.
How do you show that you're enthusiastic? Be enthusiastic. If it's a company that is solvent, it means it is serving someone, somewhere, and it's worth being interested in. Find out what good it's doing in this world. Get curious and then satisfy that curiosity.
Why do you want to work for this company? Look over your resume and think about how each of your experiences either demonstrated your devotion to semiconductor plasma processing, or paved the way for your new-found love, nationally francised dog-walking services. Note that you know the dog bite liablity statutes in all 20 jurisdcitions where this fantastic company operates.
Your Interview Will Be a Success
Most important of all, be yourself. Show your true face and your genuine enthusiasm. If it's a good fit, the company will be glad to welcome you. And if it's a bad fit (and the interviewers will be able to determine that better than you), then you'll dodge a bullet.
You're a winner either way.