This was a gift I helped my dad make so he could give it as a wedding gift. This is an attempt to build from plans that Ana posted here:
We took two long long cherry boards we had, some with bark still on the sides, and ran them through the planer and cleaned them up. Then we ran them down a table saw splitting them in half to be able to use bark ends on each side and book-matched the cherry colors, but most people wont have to worry about that since they wont be using "found" cherry.
The back board is made up of four 1x7s cuts at 28.5 inches long. You can use whatever width you want, we just wound up with 7inch pieces. Then we used a Kreg Jig to screw those together flush (see picture of back). Once those 4 pieces were together as best we could make them we sanded the edges down to make the backboard smooth and flush.
The 8 mini shelves were 1x3.5s cut at 10 inches long. The middle and bottom shelves were 1x5s cut at 24.75 inches long. Again, we were using limited wood and had to adjust our measurements to make it work. You should do the same so your shelves fit right and there is still room for you wine bottle to fit between the floating shelves.
We spaced the bottom shelf flush with the bottom of the backboard and then would space 4.5 inches between the top of that and the bottom of the next shelf. MAKE SURE YOU KEEP THE FLOATING SHELVES ACROSS FROM EACH OTHER LEVEL WITH ONE ANOTHER. Otherwise your shelves look off and lazily placed.
The way we placed the shelves on backboard was to use 3" screws straight from the back into the shelves. We used 8 screws per big shelf and 3 screws per little shelf. We had to clamp the shelves in place on the front of the board and trace them with pencil. Then we marked holes to drill within that trace and drilled from the front of the board to the back so we weren't guessing on the holes from behind. Then we would clamp the shelves back on and use the pre-drilled holes to mark the shelves from the back to make sure we were drilling into the center of the shelves. Then we would unclamp the shelves and fully drill the shelves by themselves while they were not attached to anything. This helped us make sure we drilled straight and never came through the top or bottom of the shelf by accidentally drilling at an angle. Also, be sure to sand off your pencil marks after your drilling is all done before you screw the shelves on or else your makes will show around the shelf. After that, re-clamp the shelves to the backboard and use your 3-inch screws to attach the shelves.
Then it was just slow and steadily clamping, tracing, drilling, re-clamping, drilling, sanding, re-clamping, and screwing the shelves on. You have to follow that pattern for each shelf or you risk ruining your shelf and if you have limited wood (like we did) that is not an option.
The pictures dont show it but we also put very small pieces of wood to keep the bottles from rolling off their shelves. These were just scraps we had lying around and tapped them in with small finishing nails.