Holding their Gaze.
Choose the right moment. Holding your crush’s gaze can be a powerful way to flirt, but you need to do it at a good time. There’s no way to plan for the exact moment, but aim for a time when you can potentially have their complete attention without too many distractions.
Catch their eye. If you’ve chosen a good moment, this shouldn’t be too hard. If they’re introducing themselves or meeting you at the door, they’ll likely naturally make eye contact. If the context is more difficult, keep your eyes on them until they notice you looking.
Keep your facial expression inviting. Let your expression be soft. This can mean smiling slightly, or even licking your lips a bit. If you let your face freeze up or come across as too serious, it might look like you're staring rather than flirting.

Maintain eye contact. Normal eye contact lasts for about three seconds. However, if you can hold your crush’s gaze for four and a half seconds, they’ll get a powerful cue that you’re flirting with them. You can even hold it longer, if you like, as long as your crush doesn’t look away.