The refrigerator that came with the apartment is extremely basic and pretty small. Plus the freezer is on the top so finding things in the frig means bending down and digging around. Since the refrigerator only have three unmovable shelves, I bought three plastic bins that fit front to back but are only about half as wide as each shelf. I use these bins to group like items together. For instance, when I'm making brown-bag lunches, I pull the bin for that job. It contains luncheon meat, condiments and breads that I want to use up. I have a whole other bin for leftovers and produce that needs to be used quickly. Then I have another bin dedicated to breads or sweat treats (like cinnamon rolls). Everything else fits on the shelves around these bins.
For drinks and quick after school snacks we have a separate small refrigerator.
The freezer didn't even have a self in it and keeping it organized was impossible. I eventually put a wire shelf in it then the stuff that goes on top of that shelf are in a cardboard box (plastic bins crack in the freezer). Now when I need something from the freezer, I pull the box, dig around for what I want then put the box back. This helps keep stuff from pressing against the freezer door - which doesn't close well to begin with. Before I started to use the box, the freezer door would keep popping open.
When we move, I'll re-use the bins. One bin will be dedicated to make-your-own-dinner-salad which we'll do nightly.