I have improved my senses quite significantly over the past few years.
It seems that our senses detect much more than we usually are consciously
We routinely ignore most of our sensory world and instead focus on whatever aspects of it we choose to be interested in. Learning to pay attention to more of the details of sensory experience is the key to enhancing your senses.
Learn to pay attention to that which you judge to be "irrelevant detail". Notice the subtleties of texture of all the objects around you, not just the general shape, color and position of the objects. Learn to listen carefully to all the subtle sounds around you. Pay attention to your senses, and you will automatically develop a greater capacity to pay attention to your senses. Continue this practice for years, and you will notice a profound difference.
Even after a few days or weeks of intense sensory focus, and the difference in the quality of your sensory experiences will be evident. It is important to pay attention to as much as you possibly can, to let yourself be immersed in your sensory world. Going for walks alone to practice paying attention to your senses can be very helpful.
There are many other exercises that can be done to deliberately improve your senses.
It's mostly a matter of practicing using your senses. When you find yourself daydreaming, simply switch your focus to your senses.
Work on seeing all the details of things you see; eventually you will see them with no effort.
All your senses can be improved simply by learning to pay greater attention to the information that they already detect.
The effects of enhanced senses include the experience of a richer, more detailed world, a greater awareness of that which is usually ignored, an increasingly accurate perception of one's world, and many other benefits.