If you choose to remember your past, you will ultimately attract more experiences that are similar to the experiences you remember from your past due to the law of attraction. The only way you can even remember your past is by maintaining a vibrational frequency that matches it. The memories you can access today are vibrationally similar to the vibrational frequency you currently maintain, for every thought you think, including memories, matches the vibrational frequency you maintain and thus you cannot remember memories that are not harmonized with your present vibrational frequency.
In essence, the vibrational frequency of your memories is within range of your current vibrational frequency, the way you feel. Thus, to forget the past, you simply must change your vibrational frequency enough that you are no longer within range of the vibrational frequencies you used to give your attention. In other words, you must change the way you feel enough so that you no longer feel the way you feel as you recall those memories.
To do this, give your attention to the highest, fastest, and best feeling vibrational frequency you can find in this moment in time. As you give this vibrational frequency your attention, you will begin to attract thoughts and experiences that are of a matching vibrational frequency and you will gain access to different memories that are a better match to the vibrational frequency you wish to maintain.
On the other hand, if you want to improve your memory, or gain access to memories you cannot presently access, you must do the exact opposite and attempt to align with the vibrational frequency of the memories you want to access. To do so, you must give more of your attention to thoughts that are similar in nature to the memories you want to access. For instance, if you want to remember something about your early childhood, you should purposefully think thoughts about your early childhood, thoughts you can easily access right now, and as you do so, you will begin to vibrationally align with the selected thoughts and you will then gain access to more and more memories of a similar nature until the selected memory can be easily recalled.