moodier
Sad is a short adjective so you just add -er to make the comparative form = sadder You add -est to make the superlative form = saddest
redder, reddest sadder, saddest
The degree of comparison for "sideways" is the positive degree, as it simply describes the manner in which some people sleep. It is not being compared to anything else in this sentence.
unchangeable, steady
No, the word moody is an an adjective. The noun form is moodiness. The exception is when Moody is a person's name, then it is a noun.
moodier
The comparative degree of "holy" is "holier."
Teapot is a noun and, as such, does not have a comparative degree.
The comparative degree is wider.
"Less" is the comparative degree of little.
Thriftier is the comparative degree of thrifty.
The comparative degree for "lush" is "lusher."
The comparative degree of "light" is "lighter."
better for its comparative and best for its superlative
"Speed" is a noun and a verb and, as such, does not have a comparative degree. The comparative of the adjective speedy is speedier.
"Less" is the comparative degree of little. The superlative degree is least.
"More important" is the comparative degree of important.