firstly complete wall putty inside, then flooring, door frames, at last paint

These are some of the colors that I liked.

Hi Shivam, I hope you are doing good. There is no particular tile size that may look good as it completely depend kind of design you have in your perspective. If you are looking at more traditional interiors then generally smaller tiles with motifs or emblems look good which have a representative geometrical or floral patterns. If you are looking at more modern interiors then generally bigger tile sizes are preferred for clean look less joints.  Regards, deSigneR

Hi Shivam, the best size is either 300mm x 300mm or 600mm x 600mm. The reason is - smaller the tile size better the maintenance of slope to achieve drainage of water. Also, use anti skid tiles to avoid accidents.