i'll tell you a method that worked for multiple of my friends.
pretend you're not attracted to him anymore.
talk with another co-worker about how you're very into a guy at your gym/hobby place/cafeteria or whatever, and make sure this info gets to him someway. don't be too giggly and obvious though or it will just hurt your chances more because he will understand you're trying to make him jealous. be as natural as possible.
act smiley when looking at your phone, show a picture of some random model to your co-worker being like "isn't he cute? found this on his insta profile". pick a low-level, not overly fake and too attractive of a model ofc. be ready to come up with a smooth excuse if your colleague asks to see more or his contact.
all of these instances (and more you can come up with) can't happen in a single day. a couple of weeks to pull them all out will suffice.
this will be a blow to his ego, he will start to wonder why you're not focusing on him anymore and now like another guy, and it will trigger the classic moid competition response.
be mindful of how you behave around him. don't change. don't get cold, don't fake happiness, or pretend you've moved on.
of course, if you stole glances at him a lot, tried to find excuses to talk with him and so on, that needs to go. you need to be yourself, with a neutrality twist now.
now you have his attention, but this is not enough, especially not for a moid who is the loser type and is used to rejection and low self confidence.
this will make him wonder, but not approach you or develop an interest.
this is where you need to work on yourself, inwards and outwards.
keep in mind that moids love to conceptualize women in stereotypes they learn from stuff like porn, anime and even just talking with other scrotes. archetypes are comforting and attractive to them.
so try to find your own style that fits a niche. are you tall and modelesque? are you petite and cute? or a cool girl next door?
find what works best with your appearance and embody that in your style and attitude. there are many other options to choose from.
even if you're not his "type", that is okay. men are fickle when pussy is involved and anything can be attractive to them.
don't forget the looksmaxxing. pick dresses that flatter your body type, get your hair and eyebrows done if you haven't yet, in a way that fits your features. dont be afraid of making a complete revamp too by changing hair color if it fits the image you're portraying better.
use natural make-up, just a little bit. make sure your every
make-up choice makes sense in the context of all your facial features. it makes a world of difference.
i can write more on this if anyone finds it useful or interesting.
but this is loosely what worked for people i know.
this glow-up cant happen all at once or it will be weird by the way. start slow. you will also feel more confident and happy and probably catch the attention of other guys as well. this will make him think things with the guy you have a "crush" on are going well, and add to the play and his jealousy.
after you have him hooked a new phase begins but it doesnt require the same effort at all.
good luck anonette <3