Firstly, during a conversation should always be attentive to their words. Before you say something - think.
Secondly, you need to respect other people's secrets. If a person has promised to keep someone's secret, he must keep his word. In the future, it will make people treat you with great confidence.
In order not to spill the beans, the best solution is to simply ask yourself the following setting: "I did not say," and always remember about her. As the saying goes, silence - gold.
Thirdly, it is necessary to learn a very useful skill: translate seamlessly conversation on indifferent subjects. Because of this a person can easily avoid difficult situations. Realizing that the conversation goes on a dangerous track, it just translate it into safe plane.
Fourth, it is important to maintain composure. Much of what later regret, people say just in a rush of emotion (eg, from evil). It is especially important to keep yourself in the hands of the other person is a bad person or you opponent.
Observe polite tone in conversation, it will help you to hold back. Etiquette, in principle, such a thing to which it is often used when other options to no good cause can not.
You can have several fun "domestic preparations" - in case of need they will help defuse the situation. The main thing is not to repeat them in a conversation with one and the same person, because then it would not be so interesting.
If you have already established the view that the people you are talking to, then this is for you a very big plus. You will already have an idea of when and what to say and when - to remain silent.
Keeping in conversation a few such simple rules, just to hide the information from the interlocutor.