Taboos
In Qatar, which is a conservative nation, it is best to avoid discussing sex, religion, or politics. Even if your beliefs on these subjects seem acceptable to you, you should keep in mind that they are based on a different set of circumstances (perhaps western). It's also crucial to be aware that criticizing the emir is illegal (per the constitution) and that disparaging the Prophet Mohammed is offensive.
Avoid eliciting personal information from locals, especially concerning female family members, and refrain from expressing enthusiasm for their material things. For the majority of Arabs, familiar privacy is a fundamental virtue. If you don't know the local laws, you risk getting fined or put in jail. Be careful not to bring any drugs, alcohol, pork, or pornographic items with you to the airport. You should be aware of what is prohibited from entering the nation because your luggage will be inspected.
Qatar does not consider alcohol to be prohibited, however there are severe limitations. Don't mistakenly provide alcohol to a Muslim or a youngster, for example. You can purchase and consume alcohol at hotels and eateries that are authorized to do so as a non-Muslim. Only restricted and authorized venues allow the serving of them. You can apply for a liquor license if you are an expat and want to buy alcohol from a store that is authorized to sell it. Once acquired, be sure to immediately bring it home and store it out of sight.