Every cryptic clue is really two clues in one, pointing at the same answer from two different directions: a straight definition, just like a normal crossword, and a piece of wordplay that builds the answer letter by letter. Solve either one and you can use it to check the other — that's what makes cryptics satisfying rather than just hard.
Definition — every clue has a definition hiding somewhere in it, usually at the very start or the very end. It's a normal synonym for the answer, written as if it belonged in an ordinary crossword. This hint tells you which part of the clue to trust as a plain meaning.
Indicator — a word or short phrase that signals what kind of wordplay is happening. Different tricks have different tell-tale words: "confused," "drunk," or "broken" often signal an anagram; "returning" or "back" often signal a reversal; "some of" or "hidden in" often signal a word hidden inside another. Spotting the indicator tells you which technique to apply.
Fodder — the actual letters or words the wordplay works on. If the indicator says "anagram," the fodder is the specific word or phrase whose letters get rearranged. If it's a hidden word, the fodder is the longer phrase you need to search inside. This hint points at exactly which part of the clue to manipulate.
Eggs squeezed out by a rooster! Thats unusual .. Most unusual (6)
The definition is "Most unusual" — a plain synonym for the answer. "Squeezed out" is the indicator, telling you to drop the oo from a word. The fodder is "a rooster" — with oo squeezed out, anagrams out to spell out the six-letter answer- RAREST.