A guy who's interested in you and who wants to flirt with you is going to be around. End of story. He's not going to be busy all the time, he'll make time for you. Even if he's shows his interest by ignoring you, he'll make sure to be ignoring you in person.  Remember, it's hard to flirt if he’s not even there. If he's never around, he's not likely to be flirting with you. Even if he's not physically around, he'll make his presence felt by sending texts, calling you, and making sure to show up at the same things you’re going to. A guy who's interested in you and wants to spend time flirting with you might try to impress you. When he's doing or saying something "cool" he'll make sure to check in to see if you're paying attention to how awesome he is. See if he tries to outdo his friends when he’s around you. He outdoes them in terms of the cool things he's done, he wants to outdance them on the dance floor (and show you what a good dancer he is), he wants to try out that new bike trick. A guy who likes you is going to laugh at your hilarious comments (even if they aren't that funny, especially if they aren't that funny). Your flirty banter is going to make him laugh, if he's into you. Just remember, mean laughter is not a good sign. He can laugh at you when you're acting silly, but if his laughter hurts, run away from that guy. You don't want to flirt, or do anything else, with that guy. Again, a guy who is interested is a guy who is paying attention. If he's acting very kindly towards you, doing nice things for you, helping you out, there's a definite chance that he might be interested (especially depending on the types of things).  For example: if he brings you flowers, or a little something because he thought of you (even if it's something silly), that's a very good sign. He also might do something like bring you soup when you’re sick. It shows that he's thinking of you and it shows that he's willing to help you out, especially if it's out of his way. This is a big one. A guy who has a flirty personality...

How would you rephrase that briefly using Indonesian?
Perhatikan apakah ia berada di sekitar Anda. Lihatlah jika ia mencoba membuat Anda kagum. Perhatikan apakah ia menertawakan kata-kata Anda. Perhatikanlah jika ia memberikan perhatian kepada Anda. Perhatikan cara ia memperlakukan Anda. Perhatikan apakah ia membela Anda.