Hi thanulee,
Each scene is different, and perhaps needs a different approach. To not know anything about a given scene, leads to guessing or to average suggestions.
Having said that, here some thoughts, and it is not complete, I just brainstorm about it here: (Some might not work or again no fit for your project)
•Number one is of course, get the hardware that fits to your work. There is nothing more disturbing for your creativity than a slow machine.
•Secondly, work and create efficiently, especially in modeling and using options that increase polygon count.
•Explore how much the “Level of Detail” options can support the scene.
•Use the Layer Management, to reduce the workload during set up
• Render settings should be always just a little bit over the final needs, not just crank it up and hope for the best
• Textures and shaders, are those optimized for the scene.
• Consider to export an animation as Alembic, and reload it.
• Explore the options in X-Ref.
• Replace background elements if possible with “cards”, i.e. already rendered – if the parallax allow to do so.
• Bake anything you can in textures, eventually bake the light into the textures.
• Store as much as possible in cache systems.
• Optimize Anti Alias as much as possible.
• Check the Render Settings options, e.g., Ray and shadow depth.
• … with some caution, explore other options, as ProRender
All the best