American English tends to use initial capitals for all content words in titles: in general terms, everything apart from grammatical items (articles, auxiliary verbs, prepositions, conjunctions, pronouns) is capitalised.
British English does not capitalise in titles any more. We only use capitals for words that would obviously require capitalisation if they were in the body of the text: the first word, proper names and the pronoun 'I'. All other words are in lower case. To the British eye, capitalised titles look rather old-fashioned.
I'm an editor, and I follow the British no-caps ( prose style) convention unless I'm working on a text which is specifically American English. When I work on American texts I follow the first convention, but I'll admit that I have never heard the more-than-three-letters rule. Personally, I would leave words such as 'near' in lower case, but perhaps other editors might capitalise it.