To improve concentration, twice a day, practice holding a specific object (like pencil, your house, etc) in mind steadily for 5-10 minutes.

The item should have some detail that you can imagine. Some good examples: an apple, a pencil, the face of your child or pet, your house as it looks from the outside, and so on. Choose something you won’t have trouble picturing, but something that requires you to focus in order to see it clearly. Call up a strong mental image of it, and then try to keep your focus on the object for a full 5 or 10 minutes without losing your focus.