My dad would come home from work everyday and put his wallet keys and other contents of his pockets in a certain spot. The same spot everyday. I do the same thing with my keys and I try to put my notebook on the same spot as well. Friday I put my notebook in a different spot and this morning I left the house without my workbook.
I always thought of what my dad does as a habit and maybe it is but it is a habit for a reason. There are two types of memory episodic and procedural. Remembering to place and retrieve keys every afternoon and morning is an example of procedural. Remembering an experience, like a family trip to the lake or swimming out to the deck at the lake and resting in the sun while your muscles recovered from the exhausting swim out and working up the energy to swim back before the sun set is episodic.
It can be easy to forget either type of memory. Here is an amazing article outlining what happens when we forget. Essentially the article goes over at a basic level how episodic memory works. Memories are chemical changes at connection points (synapses) between neurons in the brain. Each memory is stored as thousands or millions of synapses. Chemically procedural and episodic memories are the same just different parts of the brain are involved.
Basically our memories are chemical reactions creating a story. The procedural memory is less complex than episodic and therefore easier to remember. Examples of procedural memory are driving a car, leaving keys near the door and riding a bike.
It seems the trick to remembering anything is to always be present and make connections with as many neurons as you can. Smell taste and feel every moment of everyday. That way the moment becomes a memory with many hooks in your brain and you will have a rich experience even in the mundane.
In case you were wondering I indeed did forget my notebook this morning.