It's probably the most common request a bathroom designer can get - I'd like to get a bathroom that's, you know, like a hotel bathroom or spa bathroom!
First up, limestone or travertine tiling. This doesn't have to be natural stone. There are many decent quality tiles out there that double as the same effect, mostly porcelain. Always go for a large format tile. 45cm x 45cm porcelain tiles are generally the best but feel free to throw caution to the wind and go up to 60cm x 60cm! If you have any awkward curves, or are intending to do a wetroom floor, check out some botticino mosaics. They are more expensive but look around online - there are many decent offers around. The effect can be stunning in a wet room shower enclosure. If you can, tile up to the ceilings or the pitch of an eve. Use ivory grout as this will blend in better with the limestone colour and not look like a white grid. If cost is an issue, tile full height around the shower area and around a 45cm tile height above the bath edge. Finish the edge of the tile in a decorators caulk painted room colour or use a nice chrome flat edge tile trim on top. You could leave the other walls to just be painted and have a 15cm tile skirting around the rest of the room. Then paint the remaining walls or ceiling in an ivory or stone colour. Dulux Neutrals range offers complimentary colours to this scheme which will also set off the tones of the limestone. The handy thing about these painted walls is that you can add a personal touch with a framed picture which will inject an interesting element to the space.
Basin Vanity - something in dark wood tones. More expensive cabinetry will be made from Wenge or American Black Walnut whilst cheaper cabinetry could be dark-stained oak. Either way, these are the items to look for. Some will come in kits including the basin and waste but, if not, go for the following. Vessel or deck-mounted basin - either stick to a minimalist china white or go for something spa-chic like glass or cast iron. Remember that glass needs cleaning! Leave residue in there after each wash and after a while it will resemble the before item of an anti-limescale advertisement. You'll need a tall monobloc basin mixer to feed over the basin and there are many manufacturers who produce this extra tall version of their normal basin taps.
The space around the base of the sink can hold your soap dispensers and hand creams whilst the cabinet itself could be a cupboard or handy drawer. This can either be wall-mounted (a bit more costly but more spacious) or have legs. Add a nearby hand towel rail and maybe a shelf (glass or matching dark wood). Hang a mirror above the basin with matching dark wood frame to tie in with the vanity unit.