Lead off with a Hello: "Hello" or even better, "Hi."
Enter Your Name: ("I'm [Your Name]", Or "My name is [Yout Name]")
Offer useful information: say a little about yourself, so much as the context would enable. For instance, if you go to a party where people don't already know your profession or what interests you!
Positive Attitude: Smile, be pleasant. It makes you sound professional
Prompt: Ask the other person a question that is relevant to what's happening right now (trap, line), like "How bout for you?" or "What brings you here?"
Practice, and Be Brief: Practice your intro until you can say it comfortably in different situations, too long to read-aim for 30 seconds to a minute.
E.g., "Hi, I'm [Your Name] I am a software engineer at [Company Name]. What do you do?" Adapt it according to whether you are in a formal or informal environment.