You can roast both millets and moong dal before soaking. that gives colour to the Pongal.
If you want the Pongal to be grainy, reduce the water by 1/2 cup water.
You can add milk after mixing it with jaggery for a richer taste.
Along with cashews, you can add raisins.
I normally add the whole cardamom and remove it. However, if you have powder or you can make powder to add to the Pongal.