Hi, Roopa, unfortunately there is not like a magic formula for this, the best way to get better render in ARCHICAD will be practicing, and learning to understand how Cinerender works in ARCHICAD.
You can watch the videos in the GRAPHISOFT Youtube channel about Cinerender, since AC18. There are also more video tutorials in Youtube from others sources.
Then out of Cinerender, you can also get some renders plugins for ARCHICAD like Maxwell Render, etc.
