Summarize this article:

If someone doesn't respond to your flirting or rejects you outright, let them go. Don't dwell on what you could have done differently, and don't try to change their mind. At this stage in the relationship, take what your crush says at face value. Look at a "no" as an opportunity to meet someone even better. Remember, this will take time. Don't be discouraged if you continue to have feelings for your crush. Just do your best to interact with new people, and don't be tempted to continue trying to flirt with your crush. Let yourself be sad. It's fine to take a day or a week to wallow a little. Vent to your friends. Treat yourself to a nice meal. If you've been flirting with your crush for a while, but you're still not sure whether or not they return your feelings, it can help to ask friends. Try to ask friends who know your crush fairly well. Sometimes, an objective opinion can help you understand what someone really feels. If your friends think your crush is interested, it may be time to be more blunt with your crush about their feelings. Just ask them like this: "Hey! I have a confession to make. I have been really crushing on you lately. Just wondering if maybe you felt the same?" If your crush returns your feelings, let yourself enjoy the moment. Keep flirting, and keep things light-hearted for a while. Don't feel pressured to progress into the serious stage of a relationship too quickly.

Summary:
Learn to take a no. Get a second opinion. Celebrate returned feelings.