Hi Ravi. We would need more information about what you like (more pics in your idea books would help) to be specific, but I think the key to the palatial look is rich, varied texture and light reflections. Think of velvet cushions, silky curtains, a deep-pile rug (not shag) with a sheen. Where I am, in South Africa. Plascon has a wonderful suede paint which could bring deep, luxurious feeling to the walls. Some wallpapers can do the same thing. Be judicious with ornate features and such things as gilding, but by all means use them. I wouldn't go overboard on gilded furniture, but a single chair with restrained gilding might be lovely, or a gilded lamp. Cut-glass vases placed to catch the light from the windows. And I wouldn't choose more than one big ornate item. You might start with a traditional rug or a big tapestry. Not both.

Another really important aspect is the effect of the lighting in the evening -- and I think you could certainly consider a smallish chandelier.

But the starting point is to search Houzz and Google images for rooms that have the feeling you like, and then try to work out what you like about them. Then perhaps post another dilemma as you get to the point where you can tell us more but want advice on specific things.