How to change my first impression?

I like this guy (Same guy I've asked, like, 4 questions about). I made a really bad first impression of being a psycho maniac weirdo (with my friends help! ;1



We sit together in class, so It will be easy to talk to him. How do I change my first impression and make myself seem cool and confident?



I really like him and have been watching videos about how to flirt, hair, how to make guys like you, etc. I REALLY NEED HELP!



I think just being myself would do it after a while (an emphasis on AFTER A WHILE) but I get all shy and bumbling around him and I get so flustered.



How do I present myself well and make him change his mind about me?How to change my first impression?
I would just start a conversation with him about that day. Say you were having a horrible day. And just be calm and smile a lot.How to change my first impression?
Whitney took the words right out of my mouth. that is the best thing you could possibly do.