The Australian Commonwealth Style manual says:

Sentences should always start with a capital letter. Initial capitals should also be used for proper nouns and for proper names (the names of specific people, places and organisations). When organisations’ names are reduced to a generic element, the capitals can usually be dispensed with; capitals are retained, however, if the shortened version still carries a specific element. Thus, the Attorney-General’s Department becomes Attorney-General’s, but ‘the department’.

Like punctuation, capitalisation is being influenced by minimalist trends, which has implications for business writing. We now use fewer initial capitals.

Fewer initial capitals are used for respect
Many business writers have a tendency to use initial capitals out of respect for generic words, such as team leader, department and management. Unless, you are naming the job title of a specific person, you don’t need initial capitals for position descriptions.

The team leaders met.
Team Leader Thurston Smith said…

A few ‘respect’ capitals still remain – most organisations refer to the board with a capital B, and Australian Aborigines are still referred to as Indigenous.

Initial capitals are used in titles, but not headings
Title case is used for the names of titles, such as books, Acts and the names of organisations. In title case, every ‘important’ word has an initial capital. Book and magazine titles are also in italics.

Pride and Prejudice
Department of Social Services

Sentence case is used for headings. In sentence case you just need initial capitals for the first word and proper nouns.

Colons and semicolons

Specific capital usage
Some capital usages are fairly universal and others are a question of style (e.g. whether to capitalise President and Queen). If in doubt, trust your preferred dictionary and style references.