Well hot dang! I never thought the day would come that I'd actually see one of these DIY Pinterest projects through to completion - but it's here (hold for applause).
I've documented my journey, but here is the link to the original project source.
You will need: 4x4 inch tiles, Mod Podge, felt, hot glue gun, paint for edges (optional), scrapbook or other decorated paper, and a good acrylic sealer.

For this set of coasters, I used scrapbook paper. I wanted my tiles to look like little log rafts.

Place the tile on your paper, trace, then cut out a 4x4 square to fit on your tile. Make sure the edges don't hang over the side. Mine did (just a bit) and I ended up having to put extra coats of Mod Podge on the sides to try and even the ledge out.

Now, you can paint the edges of your tiles if you want. I did, because I wanted the look of real log rafts (it made a difference). Your paper choice may not require painting the edges. Oh - almost forgot... if your tiles have ledges kind of sticking out on the sides - sand those down. It only takes a few seconds, but looks better on the final product.
If you don't paint the edges, go right into the Mod Podge. There are various kinds (I must have spent an hour reading labels when I went to buy my first bottle), so here's what I used.

Mod Podge the surface of your tile and center your decorated paper on the tile. Make sure to smooth your finger over it to get out any air bubbles or product build-up and bumps. Once that's dried, Mod Podge over the surface and sides of your tile. Let it dry. You'll want to do anywhere from 4 - 6 coats of Mod Podge that way. Make sure to let it fully dry in between coats. I did not Mod Podge on the back of my tile.
Once you're happy with the surface, seal it. I used about 3 coats of the following on the front and back:

Once that's fully dried, time to get to the bottom of our tile. We don't want it scratching up the furniture, so you can do one of two things. One - those little stick on felt rounds. Two - cover the entire bottom of the tile in felt. I did two. I think it looks more put-together. Just cut a square of felt to fit your tile (again, better to be a little smaller than your tile so the edges of the felt don't hang over the tile).

Then hot glue that felt square to the bottom of your tile. I like to start in one corner and apply the hot glue a little at a time to make sure it's really stuck on there. See how nice that looks.

Finally - put a drink on it! You're done :)

In all reality, that water bottle will magically turn into a wine glass very soon.
Love to craft? Or at least love the idea? Follow along and pin with me on Pinterest HERE