Install a small spring tension rod shelf to add more space to cabinet for spices. The tension rod is strong enough to hold the smaller spice bottles and they no longer get lost among the larger bottles.
150 Dollar Store Organizing Ideas and Projects for the Entire Home - DIY Hanging Baskets for Under the Sink Small baskets with handles are great for adding shelves when you need them. You can use these under the sink or in your entertainment center.
I looked over these and there are really great and clever organizing ideas. Ideas to Help Organize Your Home and Your Life. This is the mother load! I really liked the idea of using a over the door shoe rack for the linen closet