The floor is the least of your worries. Acoustically speaking, you actually want a hard, live floor because that is one of the cues that our brains subconsciously want to reference because it is familiar to us. Carpets went out with the 70's. 90% of pro studios will have a hardwood, linoleum, concrete, tile, or laminate floor because hard, uncovered floors are what you want acoustically.
The ceiling is where you want absorption, especially right over the kit, because that's where a ton of first reflections come from. If you can get your ceiling 100% absorbent then acoustically it is the same as having an infinitely high ceiling, which is a good thing. That is a lot of work and a lot of money though, so unless you want to put in a drop ceiling in your room with proper polyester acoustic ceiling tiles, with at least four inches of rockwool on top of the tiles over the entire ceiling and a four inch air gap between the rockwool and the existing drywall ceiling....you should probably just build a ceiling cloud over your kit. That consists of a frame (1×4's work well for this) and fill the frame with at least four inches of rockwool and cover the face with fabric. The thicker the better. 6 inches would be better than 4, but 4 will work ok and is about as thin as you want to go. Once again, you'll want a 4 inch air gap between the top of the cloud and the existing ceiling, so hanging the cloud from eye bolts or hooks screwed into the ceiling is the way to go. You'll probably want your cloud to be at least 6'×6', so for stability, you might consider making 2' wide sections and placing them next to each other. Hanging some space couplers directly under the cloud will increase the cloud's effectiveness as well.
Drums, more so than any other instrument, depend on the acoustics of a room for a good overall sound, and they sound absolutely terrible in a small, dead, overly absorptive room. With that in mind, your going to want a bit of absorption on your walls in places to cut down reflections and flutter echo, but with that said, you don't want too much or you'll suck all the life out of your drums.
A popular design for drum rooms uses absorptive panels on the back wall behind the kit and maybe one or two panels on the side walls on both sides of the kit. The standard design for these panels is a 2'×4' wooden frame with at least 2" (once again, the thicker the better...) of rockwool or Owens Corning 703 rigid fiberglass (rockwool is cheaper, but you get a more pro looking panel with 703) and a fabric cover. An airgap between the panel and the wall is good for this too (like the ceiling cloud) so some people put pegs on the back side of the panel to stand them off the wall a couple of inches. The new thing is to place a skyline diffuser in the center of the back wall, right behind the kit, so that end of the room isn't too dead and it helps put back some air and life into the mids and highs from the drummer's perspective. They are a pain in the ass to build, but if you're serious about this and want to put the time in, then I can hook you up with plans for how to build one.
If your room sounds really boomy in the low-end then floor-to-ceiling corner bass traps are in order. Bass traps go in the corners of rooms because that's where bass frequencies build up most in a room. There are many different types of bass traps, but the superchunk trap is the simplest to make, and by all accounts is as effective as any for most situations. These are made by stacking triangular sections of rockwool, placing them in a frame, and covering the frame in fabric. The fabric used for all these panels and traps should be very gas permeable. That means when you are at the fabric store picking out your fabric, make sure you can breathe through the fabric very easily. Just hold it up to your mouth and try to breathe through it. If you can't then your traps will end up reflecting a lot of higher frequencies instead of absorbing them. Also, more so than the other traps- when it comes to bass traps, the thicker the better. Low frequencies have the most energy and require a lot of mass to be absorbed. To be effective, make sure the face of your corner trap (the hypotenuse of the triangle that spans the gap between the two walls) is no less than 18 inches, 24 would be better...If you couldn't be bothered building anything but you have bass issues in your room then you can simply stack bags of pink fiberglass in the corners of your room and that will work pretty well too. You don't even need to open them. Just buy them at home depot or wherever and throw them in the corners. If your room isn't boomy though, then don't even worry about the corner traps. If the room isn't bassy to begin with and you put the corner bass traps in anyway, then your bass drum will likely sound very flat in the room.
That is a good starting point for acoustical treatments. If you want to tweak the sound of your room further then do some research on slats, QRD diffusers, and poly diffusers. Diffusion deals with reflections and flutter echo by scattering sound instead of absorbing it, so they don't remove energy from a room, which is a good thing when it comes to drums. The more life you can keep in the room without annoying echoes, the better your drums will likely sound in the room. Covering the entire front wall with QRD diffusers is quite popular nowadays. They are expensive to buy and quite involved to DIY, but just PM me if you think you might want to try to build some and I can send you some plans.
Slats are also very good and are worth researching as a cheaper, simpler substitute for diffusers. They scatter sound as well, and you can EQ the room a bit by varying the width of the gaps between slats. Narrow gaps attenuate bass and augments mids and highs. Wide gaps attenuate highs and augments lows (a good thing where cymbals and bass drums are concerned in smaller rooms). Using BOTH slats and diffusers is best. Slats for scattering and EQ, diffusers for life and air.
Also consider making your various different panels and treatments on stands so you can move them around the room and experiment with what type of treatment you like in different locations. I plan on mounting all my treatments on French cleats (a type of rail mounting system for walls) so I am not stuck with a specific room treatment and can change things around as I please.