Question

What to do if not getting a nice texture of watercolour even on watercolour paper.(300gm)

Answer 1

You could use a hair dryer while painting. Blow dry the paper to the point when it's almost completely dry between applying each layer, so watercolor brush strokes came out well defined and soft-edged at the same time. It gives watercolor a delicate, crystal-translucent look.
Be careful not to over dry the paper or blow the wash around.