If you’re interested in men, studies have shown that men often mistake signs of friendship as signs of desire, so don’t expect your guy to be all happy when you reject him. He honestly thought you two could have something special.
Before making a move, make sure that’s exactly what you want and you’re not simply mixing things up. It’s pretty easy to project romance just for it being convenient. [1] X Research source
Try to let your personality shine through, so that your date knows that you’re still who they think you are, and that the only thing that has changed is how you’re going to act towards each other. A skirt is fine, but don’t go all the way with a dress. That says “OK, I am trying way too hard, and I am extremely nervous”. Unless you’re at prom, or a dinner, or a party. Hopefully, it should be just the two of you for a first date. Anything else isn’t private enough. Keep it simple, although less casual than usual.
Keep the lips firm, yet open. Don’t let your mouth hang open, but don’t be tight-lipped. You don’t want your date to think that you don’t like them. If you’re going in for a second kiss, go for another 10-20 second one. No tongues on the first date. You don’t want them to think that you’re different than who he thinks you are, which is why they like you! At the end of the date, hopefully you can both say that you’ve had a lot of fun, like you used to, yet your romance was the key ingredient. You’re still best friends, except you’re more now, so hugging is great too.