DON’T say a number. Why? you have the least amount of leverage possible at this point, assuming you’re early in the interview process. You haven’t finished interviewing with them, they don’t know if you’re any good or if they even want to hire you. So you can’t command a high salary right now. If you go too low with your price, they’ll hold you to it later. Go too high? You’ll scare them off before they even know what you’re worth!
Of course, if you have an issue that is very important to you that could be a deal-breaker (like company culture), you can mention it. Just be prepared for them to take one extreme or the other. For example, maybe you only want to work for companies that buy from vendors in your home country. The hiring manager will let you know if their company does this. And if they don’t, I guess the interview is over.
If you are currently employed, you should be honest about the start date and show professionalism. You should tell them you would have to discuss a transition with your current company to see if they require a two-week notice (or some other timing). If you currently have a critical role, your potential new employer would expect a transition period.

This is a toughie, but one you can be sure you'll be asked. Definitely keep things positive—you have nothing to gain by being negative about your past employers. Instead, frame things in a way that shows that you're eager to take on new opportunities and that the role you’re interviewing for is a better fit for you than your current or last position. For example, “I’d really love to be part of product development from beginning to end, and I know I’d have that opportunity here.” And if you were let go? Keep it simple: “Unfortunately, I was let go,” is a totally OK answer.

Questions about your family status, gender (“How would you handle managing a team of all men?”), nationality (“Where were you born?”), religion, or age, are illegal—but they still get asked (and frequently). Of course, not always with ill intent—the interviewer might just be trying to make conversation—but you should definitely tie any questions about your personal life (or anything else you think might be inappropriate) back to the job at hand. For this question, think: “You know, I’m not quite there yet. But I am very interested in the career paths at your company. Can you tell me more about that?”

Start by explaining what you'd need to do to get ramped up. What information would you need? What parts of the company would you need to familiarize yourself with? What other employees would you want to sit down with? Next, choose a couple of areas where you think you can make meaningful contributions right away. (e.g., “I think a great starter project would be diving into your email marketing campaigns and setting up a tracking system for them.”) Sure, if you get the job, you (or your new employer) might decide there’s a better starting place, but having an answer prepared will show the interviewer where you can add immediate impact—and that you’re excited to get started.
"Choose an answer that shows that you can meet a stressful situation head-on in a productive, positive manner and let nothing stop you from accomplishing your goals," says McKee. A great approach is to talk through your go-to stress-reduction tactics (making the world's greatest to-do list, stopping to take 10 deep breaths), and then share an example of a stressful situation you navigated with ease.