If he or she doesn't know you then go up to him or her and try to get to know them better. If you already know them though, then just get the confidence and ask them out because to ask someone to do it for you is what people do in fifth grade or something, don't be like that. If they say no, don't be discouraged and say alright, and walk away feeling good because you at least showed the confidence of actually doing it.
Look for signs and flirt a little, stand close to him and see if he moves back or remains there. If your knees touch, does he or she move the knee or is he or she comfortable with your knees touching.
Chat with our AI personalities
If u want to ask out someone that your not shure is gay, then u should just ask them out by saying "will you go out with me?"