مَنْ كَانَ يُؤْمِنُ بِاللَّهِ وَالْيَوْمِ اْلآخِرِ فَليَقُلْ خَيْرًا أَوْ لِيَصْمُت
…he who believes in Allah and in the last day should speak good or keep silence. (Muttafaq ‘alaih: Al-Bukhari, no. 6018; Muslim, no.47)
Learn not to tell people more than they need to know. This can be difficult but be conscious of the information that you choose to divulge. People have no business to know everything about you. The less you tell, the better for you. It can save you for a whole of troubles.
The tongue of an intelligent person is under the control of his heart. When he wants to speak, he will ask his heart first. If the words are good to him, he will speak, but if they are not useful, he will choose to be silent.