capitalization - the Capital and Small Letter in Title

I am confused about when to write capital letter or small letter in a title. Like the title above, I think

The, and, in are perp, so they can be small letters.

Am I right? Can someone clarify the rules about the Capital and Small Letter in Title.

Answer

Very interesting question. Nevertheless, it's debatable as well. Some writers prefer to capitalize some words whereas others don't.

Let's look at a few points here -

a) Prefer capitalizing the first and last word of a title.
b) Avoid capitalization if it's scientific name or botanical name for the second word. For instance - Asparagus racemosus.
c) Capitalize all adjectives, most of pronouns, nouns and adverbs. Capitalize verbs as well if you want to emphasize them.
d) Try avoiding capitalization of very short words (conjunctions?) such as and or or. Also be, are, was, were, as, to, and so on [This is debatable in particular].
e) Avoid capitals to the definite and indefinite articles
f) Capitalize all the words if they are of five or more letters.

More information here.