1. 指导方针；指导原则；准则
    If an organization issues guidelines on something, it issues official advice about how to do it.

    e.g. The government should issue clear guidelines on the content of religious education...
           政府应当就宗教教育的内容颁布明确的指导方针。
    e.g. The accord also lays down guidelines for the conduct of American drug enforcement agents.
           该协议也为美国毒品稽查人员的行为制订了准则。

2. 参考
    A guideline is something that can be used to help you plan your actions or to form an opinion about something.

    e.g. The effects of the sun can be significantly reduced if we follow certain guidelines...
           如果我们遵循某些建议，日晒的影响会大大降低。
    e.g. A written IQ test is merely a guideline.
           书面智商测试仅供参考。