Titles are part of names, so they are capitalised. (article: Capitalisation in Captions, Titles and So On...) Acronyms, such as CE (chief executive) and NASA (national aeronautics and space administration) are abbreviations that have become names. They are capitalised. Some initial-letter abbreviations are capitalised (PE, DVD & NET) and some are not (laser & e.g. ). Popular use dictates how they are punctuated. Units are capitalised if they are named after a person (Newtons & Watts), not if they are not (grams & metres). (article: Should a litre be abbreviated with a capital L or a small l?) This topic has been covered in previous articles.
Skills and subjects are not specific names and do not get capitalised. Yet this fundamental point gets widely ignored. The words algebra, biology and cookery are all subjects. The Chinese language, Chinese history and the English language are special, they are already names; however the secondary words language and history are not capitalised. Skills and subjects are not capitalised unless they are a part of a name. One can use a capital letter if the skill is in the name of a textbook, course, competition or other such use or if they are at the beginning of a sentence. So, unlike in the example below, the words mathematics and maths are not capitalised.
Do not capitalise for emphasis. If one needs to emphasize part of a sentence, use bold, or italics or underline the words to be emphasised. Although try not to overdo it, emphasis is the written equivalent of shouting.
Capitalisation is for very specific punctuation uses. It is not to be randomly used in sentences whenever the writer thinks that a word is important. In the example below various skills and subjects are inappropriately capitalised. See how many such mistakes you can find.
These examples are from an important organisation with highly paid staff and the resources to do decent proofreading. When teachers check students' work in lower grades we might skip small errors and mention just one or two errors that a child might remember. However for a large well-funded organisation to repeatedly make such elementary punctuation errors shows an inability to hire a decent proofreader.