Lying requires a lot more mental effort than telling the truth. Eliminate as much of the mental effort as you can by knowing the lie before you tell it. Try to bend the truth instead of making up an entire story. It is much easier  for a person to believe something that could actually happen.  For example, instead of making up a story about going to a party, you may go to a party but lie about some of the details such as who else went and what you did. If you went out to eat with your family at a specific restaurant, you may lie and say you went to the restaurant with a date but tell the truth about what you ate. Ask yourself if you would believe the lie that you are telling. If it is hard for you to believe, the other person probably will not believe it either. Place yourself in the other person's shoes and think of the questions they may ask. This will also help you identify any holes in your story.  For example, you probably shouldn't lie about going to a party if your friend knows that your rarely go to them. Also think about the personality and traits of the person that you are lying to. You know the things that are likely to believe. What works on one person may not work on another. Stand in front of the mirror and practice what you are going to say.  If you are not well prepared, you are more likely to make something up on the spot. When you make something up on the spot, it is easier for the other person to notice that you are lying.  Consider audio and/or video recording yourself lying. This will help you identify any awkward pauses or mannerisms that you do that may give you away. The more you can practice the better. If you rehearse a lot, it should feel very natural when you talk to the other person. If possible, do not include any other people in your lie. The more people that know you are lying, the more likely you are to get caught. If you do need someone else to cover for you, only tell them what they need to know. Do not tell them your entire plan.  For example, if you are sneaking out of the house to go to a party, do not tell your friend what you are doing.  Only tell your friend, “If anyone asks where I was on Friday night, tell them you have no idea.” If you are lying about who you were out with, tell your friend your location, but do mention the people that were there. This way, your friend could confirm your location without blowing your cover.
زيّف الحقيقة. قل كذبة معقولة. تدرب على قول الكذبة. حاول ألّا تُدخل أشخاصًا آخرين في القصة.