If you are over 50 years old… have you ever put a cookie down on the table in front of you, read for a minute or two, and then looked up and see that the cookie is gone? "Where'd that cookie go? Did I eat that cookie?" If you do not have small grandkids running around the room, the chances are you are experiencing the process called "getting older".
There are things you can do to help, but for the most part, forgetfulness, of at least some degree, seems to be part of senior life.
When you want to remember something, for instance today's date, say it in a couple of ways, such as, "Today is the 12th of the month. Twelve is two times six," and maybe also add, "Twelve is six plus six." If you want to remember someone's name think of that person and connect him with the one that name originally comes from. Such as, "My new acquaintance is called Moshe. Moshe led the Jews out of Egypt." By saying what you want to remember over again in a different way it gives you double the chances of remembering it.
When you walk into a room and stop by the door and ask, "What did I come in here for?" do something else that has to be done for a minute, such as tidy the room…hang up something. Often the original reason you went in there will come back to you. Whenever you forget what you were supposed to be doing, clean up things that have to be cleaned anyway, and worse comes to worse you may not remember what you wanted to do, but at least the house will look nicer.
Some say drink coco (I don't know if it works but it tastes good). The Talmud recommends olive oil (so do the health nuts).
Most of all don't get frustrated. Frustration just makes things worse. Remember, the alternative to living a long life is living a short one. Thank G-d we still have what to do, and we are still here trying to do it.