How to creat an English name?Could you tell me some rules?

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I want to have my own English name for a long time.But I am not sure which one is suitable for me so I need your help.I called myself green before because I like the color-green,which is one kind of comfortable color.Otherwise,now I think Green isn't offical so I would like to change my English name.Can you give me some adivices? I am a lovely.quiet,and shy girl.My Chinese name is ChenZeping.