??? You turn them down because you think they're ugly? You're going to get a lot of cr@p for saying that. Weren't you taught to like someone for what's on the inside, not the out? Anyways, if you're really that shallow, then just tell them you're not interested- but do it in a nice way. Don't say "sorry, you're just too ugly" you could just make up some bs like you're not looking to be in a relationship right now or something.
Wow... how sad. You shouldnt brush ANYONE off. Do you brush off a really attractive person because they are "out of your league"? What do YOU have to offer to anyone?? Make sure you answer that each and every time you want to ask someone out.
Tell the person you don't feel an attraction to them. You don't have to say what the attraction is based on. It is truthful but it doesn't have to shred their self esteem either. It doesn't leave them holding out hope that you will be somehow "ready" in the near future for a relationship with them either. It also won't hurt their feelings when you date someone else in a few weeks. You don't OWE someone a detailed explanation about what does or doesn't attract you to them. If it's bad breath or beautiful eyes. You can say "No" with tact.
If you aren't interested then simply decline him. Tell him in a good and non-negative manner. You do not want to make enemies now (at least I hope not), so be kind about it. At the very least, become his friend. You do not have to date him, just befriend him. Remember, looks become less and less important as people age. Then personality comes into play. Not saying that good looking people don't have personality, but the point is that personality is super good too. In general, just tell him slowly and politely. Be friends (If you want) and go from there.
Easy everyone!! Usually there is an attraction or chemistry that starts all relationships. If its not there, it's not there! You should never feel obligated to go out on a date with anybody you don't want to. Especially if you are not attracted to them. There's someone for everyone and this is not it.. Don't feel bad