I'm not a nail polish kinda woman but I still like my nails to be neat and manicured. I use a 4-Sided Buffing Block to give my nails a polished and naturally glossy finish. I've been using buffing blocks for years and when used consistently (once a week for me), my nails stay smooth and with a healthy shine to them.
The sides on the block are numbered so you know in what order to do all the steps. Once you've done all 4 steps, you can stop there and be finished. I take it one step further and rub a lil oil of choice (grapeseed these days) into my nail beds for a lil more shine and "conditioning" and then apply a moisturizing lotion to my hands.
Super easy and produces results. You can get a buffer block at your local drugstores for under $3. If you try putting the oil on your nails like I do, you can use whatever oil you have on hand. EVOO's a cheap oil that delivers and most have this in their kitchen. I could also see how coconut oil would give the nails a nice shine.
I found one at the dollar store and its great!