Making the shelving not as deep will actually help to utilize more space. Not only will you be able to reach and see things in the back of the closet better, you will end up organizing what you store in there more efficiently.

If you don't want to remove them, use partitions such as small baskets and trays to help organize your belongings. I would also put things that I use frequently in the "strike zone," as to keep them at eye level and arms reach. Things used less often can go up top, and cleaning supplies, etc., can be stored on lower shelves. Think about hooks for the back of the door to hang beauty supplies and other items that aren't too heavy. Hope this helps!

I would keep a plastic bin on each shelf, and you can store everything in the plastic baskets/bins. I organize by person or by use (ie: bandaids/first aid basket). IKEA has some that look like they would fit on your shelves (you can use without the lid), but I am sure you can find a similar storage basket elsewhere.

http://www.ikea.com/us/en/catalog/products/20280207/

There seems to be quiet a bit of height between the levels if it was my place I'd built a small 2-step platform that has a base that goes half the depth of the shelf. Push that to the back. so that I wind with products are staggered in 3 tiered heights. I'd also use specific shelfs for types of products so if Im looking for a bath vs hair item.... I know its at the top shelf instead of the bottom shelf. Alternatively you can get smaller size baskets to hole everything and retrofit small wheels on the bottom for easy pullout. If youre super organized on the back of the door you can just list whats in each shelf and do none of the other suggestions