Everything has its place

If you keep misplacing something, keep it in a set place or places in each room and discipline yourself in doing so until it becomes habit.

It's usually best to put something in the first place you think of when trying to find it, even if it might look out of place there.

As an extension to this, I've found putting most of my day-to-day things in a bag/backpack etc. helps the most. It's whatever works best for you but I always keep my keys, meds, cards and a USB cable in my bag, and that goes out with me basically everywhere. Just make sure you're not carrying half your life around with you!