Walk up to someone and compliment them.

• “I love your top!”
• “Your eye shadow is so good!”
• “Those shoes are so cute!”

If they respond enthusiastically (more than one word response, makes eye contact, smiles), ask them about it.

• “Where did you get that?”
• “What palette did you use?”
• “What brand are those?”

If they still answer enthusiastically, congrats, you’ve started a conversation. Keep it going.

Edit: It’s also entirely possible you approach someone who’s shy/nervous and their responses might not qualify as enthusiastic. Personally, I risk being annoying if I’m talking to someone who seems to be alone, quiet, or shy. Keeping the convo going a little long gives them a chance to warm up to you.