Hey Ashwin! Your horizontal lines and vertical lines should be parallel if they are following the same plane. Going completely vertical and horizontal will look really static though but you can always warp your grid into another perspective afterwards.
The tissue box is also slightly out of your grid and should follow the perspective lines of the left wall if it is attached to it. Basically whenever you place a new object that breaks your perspective grid it will create a new grid with its own vanishing points (e.g the books, the small clock, tissue box), so it takes some tweaking to make it look correct - especially if you're eyeballing it!
Very easy fixes but your work looks great! Keep it up
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