First, it would be proper to make sure the host is seated before you sit. Unless the host is male, in which case he would wait until all females are seated until he takes his seat. Likewise, in any situation, such as a job interview, you should never sit unless invited. Next, you will want to put the napkin on your lap. Avoid wiping your face or nose with the napkin. If you need to get up, leave the napkin on either side of your plate.
Try to order within the same price range as your host. Never order the most expensive menu item. Also avoid ordering alcohol unless the host is ordering it, and even then, never drink more than your limit in a business situation. When food is served, you should not begin eating until everyone has received their food.
Any food dish on the left is yours; any glass that is yours is on the right. Most silverware is set so the one you will use first is on the outside, and you work your way in. For example, the appetizer fork might be on the outside, then the salad fork, then the dinner fork. When you are finished with your meal, rest the silverware crosswise on your plate to indicate you are done.