It's so important to be aware of your body language. You might be unintentionally giving off a vibe that is negative or unengaging and not even realize it. It could be something as simple as smiling that could completely change your aura.
Every time you walk into a room, think about how you want people to see you. I always try to be my most positive self, which I want reflected when I am out and about socializing. I make sure to stand straight, shoulders back and chin up. I smile and look around and try to make eye contact with several people. A lasting first impression can happen in as little as 60 seconds. I want people's first impression of me to be a positive one.
On the other hand, if you walk into a room hunched over, staring at your phone, no one will notice you. At least not in a positive way. You are not engaging with the crowd and you don't appear wanting to be there. There is nothing less appealing to me than having a conversation with someone who is constantly checking their phone or looking around the room. If I begin speaking to someone, they have my undivided attention. Of course sometimes you will need to check your phone so it's perfectly fine to excuse yourself to do so but make sure you're to do it in a respectful way.
When engaging in conversation, look the person in the eye and actually listen. Don't think about what you're going to say next or compare what they're saying to something that's happened to you. Listen and respond only after they're done. Always let other people have their turn speaking - don't hog the mic!
Being able to make a connection in real life is so important now that we live in a digitally biased world. Smile, make eye contact, put the phone away and listen. You'll leave the party with many more numbers this way, rather than Instagram handles.