Rule 1 : While comparing the objects, we should see that a noun is compared with another but not with some other word.
Ex - The population of Delhi is greater than that of Meghalaya.
The climate of Kashmir is better than that of Uttar Pradesh.

Rule 2 : In comparisons, the monosyllable words like "hot / easy / tall / small" should not be used with more / most.
Ex- This question is easier than that.
He is taller than Kumar.