Bathrooms can be a bear to keep organized no matter if you share them or not. The easiest solution is to pull out everything you use when you get up and ready! See how many items you have, determine what order they are used, and purchase small storage bins to fit under your sink for those items.
Place the items in the bins in the order you use them – so if you do makeup before you do your hair, put all your makeup in one bin. Pull out only that bin when you do your makeup and put it back when you are done. Pull out the bin with your hair supplies when you are ready to do your hair and put it away when you are done. You can do this with everything in your bathroom – imagine how nice it would be to pull out the cold and flu medicines, or pain relievers all at once in one bin!
The key is to only have on hand what you will be using NOW and put it away IMMEDIATELY after you are done with it. Then you will know where the items are at any time. Give it a try with one or two categories to see if that will work for you. If you share a bathroom, you can also do a bin for each person for their personal items, and more general bins for shared items (toothpaste, aspirin, bandages, etc.)