Rule 5. There are a few adjectives that are accompanied by ‘to’, like, senior, junior, superior, inferior, preferable, prefer, elder. Do not use ‘than’ with these adjectives.
Degree of adjective examples:
Incorrect: I am elder than her.
Correct: I am elder to her.
Incorrect – This car brand is superior than that.
Correct – This card brand is superior to that.

Rule 6. When comparing two things, similarity should be there, i.e. similar things should be compared.
Examples of degree of comparison:
Incorrect – This wall colour is more beautiful than the old one. (wall colour is compared with the wall)
Correct  – This wall colour is more beautiful than that of the old one. (compare wall colour with wall colour)