The first thing I did was line the inside of the cabinet with white sheet vinyl, tacking it down with small nails with heads to hold in place. This lightens up the cabinet so you can see inside. Then We put a half shelf across each cabinet. The lesser used items go to the back under the shelf, then frequently used items go on the shelf and at the front. This actually gives you 1-1/2 storage area. Then in some cabinets on the other side of the room, we put in those pull out wire baskets. Our lower cabinets have a shelf which got a basket too! LOVE them!
You can purchase slide-out shelves or you can use a rectangular tray (like a cookie sheet) to slide out. I'm short, and I had trouble reaching the things near the back of my shelves. I just purchased plastic turntables (some double- stacked) at Walmart. Now I can reach everything on my shelves.