Women make friends and don't recognize people.
Personally, the first thing to do is to know the basic information of boys first, so that you can communicate more with the girls in the next class. You know, girls can be good friends as long as they have hobbies. After doing this, you are asking the boy's preferences. He often appears in some places, such as basketball courts. As long as he is here, you will go and see it. Just watch quietly, watch for a while and then leave. If you persist in this way, it will be difficult for him to pay attention to you. Or you can tell him to find a girl in his class, and after a long time, he will know you.