The memory palace is an interesting technique used to remember simple to complex list of items efficiently and easily. The idea behind this technique is to make a imaginary connection or links between the objects that you want to remember. If it's numbers that you want to remember, then convert/map that numbers in to some visual objects. Then create a story around those objects in imaginary palace. Next time when you want to remember those objects in the same order, you can just take a simple walk through the memory palace. You can easily remember the the objects in the same order easily by doing a just walk. This works.
This works because our visual memory is more powerful than verbal memory. So, next time when you go grocery shopping, just create a story of potatoes and onions instead of feeding in your phone. At the first the time, it may take some time. But when you practice it, you will master it.