If you invite someone to lunch and you're using that opportunity to learn from her, gather information from her, or get advice from her, you pay for lunch. At a networking or business lunch, who pays is not determined by level of success, influence, wealth, or gender. Typically, whoever initiates the lunch as a means of gaining value is the host for the meeting and thus pays the tab.

When dining with peers, friends, or coworkers, it's common for each person to pay his own way no matter who initiated the meal (unless it's a special occasion, like a birthday or a celebration of a promotion).

When it's your role to pay, be as straightforward and yet discreet as possible. When the bill is brought to the table, place your hand on it immediately and place it next to your plate. Claim it!

Send a note of thanks whether you paid for lunch or were treated to lunch. If you're the one who paid, you still want to thank the other person for his time and the value you received from having a chance to meet with him.