Memory:

1. Prayer is a segulah for developing a good memory (7:5).
2. Fasting and giving charity, especially charity for causes in the Land of Israel, help against forgetfulness, and you will be able to develop a good memory (37:3,4).
3. Clapping your hands when you pray sweetens the force of severity in the world. This is one of the ways of ridding yourself of forgetfulness and developing a good memory (46).
4. You must be very careful to cultivate a good memory and not to fall into forgetfulness. What is a good memory? It means constantly keeping the thought of the World to Come in the forefront of your mind and never forgetting about it. It would be a very good thing if every Jew were to make it a daily habit, as soon as he opens his eyes in the morning and before he does anything else, to bring to mind that the World to Come is the only true goal. He should do this as soon as he wakes up. This is the concept of memory in general. And it has to be followed through into every detail of the day. With every thought, word and deed which God sends you every day, you must broaden your understanding and perception of God. You must understand that every one of them is a hint which God sends you in order to draw you closer to Him. God Himself is infinite and without end. But He `contracts' Himself, as it were, to our level, using all the experiences which He sends us each day, in order to signal to us and guide us. It is up to us to recognize this and find the messages in all the thoughts, words and deeds which are sent to us, in order that we may reach a deeper insight and come closer to God. But it is necessary to understand that the only way to broaden and deepen your perception of God is in a measured, orderly way (54:2).
5. There are people who have the ability to interpret the messages contained in all the things around them, including even secular affairs. But it would be wrong only to pay attention to these signals to the exclusion of other sources of spiritual guidance. The perception of God which comes from the study of Torah is on a higher level. Thinking about the hints contained in material affairs is good up to a certain limit, but that is not sufficient. You should pay attention to them only as much as you need to but no more. And even, as here, when you take from the world just as much as is sufficient for you, you should still give a part of what you take to charity (see Mammon 27). If you develop your memory in the right way, as we have explained, great tikkunim will be brought about in the upper worlds and the unity of God will be revealed. However, the great mass of people do not have the level of understanding which is necessary to grasp the significance of the hints God sends. For them the same effects are accomplished through sleep, and when they observe the mitzvot of tzitzit and tefilin, learning Torah and praying and going about their business honestly and in accordance with the law (Ibid.).
6. If you want to guard your memory, take care not to fall into the trap of an evil eye. This spells death to the heart and gives strength to the power of forgetfulness (Ibid. 4).
7. The evil eye can appear in many different guises. People can become very jealous when their friends are successful, and they look on them with an evil eye. This in itself can manifest itself in different ways. You must be extremely careful never to be jealous of a friend at all. Pray to God and ask Him to save you from the evil eye. And if you find that someone else is directing the evil eye against you, if you feel you lack the strength to stand up against it and humble its power, then you must run from it and flee in order to escape (Ibid.).
8. You must also take care not to talk in a bad way. Talking maliciously and derogatorily about other people is very damaging to one's memory. If you work on yourself and even force yourself to be happy, it is a help in developing a good memory (Ibid. 5).
9. When it comes to Torah and serving God, you must guard your memory carefully. But still, forgetfulness does have its advantages. Anything which distracts you from serving God you should forget about completely, especially the distractions which come when you are praying. Usually they consist of worrying about the past and wondering if you did this or that right. But as soon as something is over and done with, you should simply put it out of your mind completely. Make this a habit. Just ignore it completely and don't even start to think about it. The same applies to all your worries about past transgressions and other mistakes. Just put them out of mind completely and forget about them, especially during your prayers and devotions. In fact, there is nothing much to be gained from thinking about them any time of the day except in the special time you set aside for meditation. This is the time to be heartbroken and to express all your thoughts before God. You should think about everything you did wrong. But for the rest of the day you should forget about these things completely. Simply serve God with joy, especially during your prayers (Rabbi Nachman's Wisdom 26).