When using US English, the term is always no one (two words). Within UK English, some may accept the hyphenated version, no-one, but under no circumstances is it noone (one word).
There is a big difference between an em-dash, en-dash and hyphen. They have different uses. But all hope is not lost. Your word-processor will render them while typing. Here’s how.
If you are using UK English, it is always all right (two words). According to the Oxford English Dictionary, alright (one word) is not acceptable. However Merriam-Webster states, “[Alright] is less frequent than all right but remains common especially in informal writing.”
The word data is plural. The singular form is datum. The data are… The datum is… While correct, I’ll admit it does feel weird to say. My recommendation is to charge your sentences that involve these words to remove the is/are or was/were. The data shows…
It’s a common mistake made, and one I often have to look up, just to reaffirm what I already know. Affect is the verb, where effect is the noun. It doesn’t help the confusion when the word “influence” can be used to replace both words.
It’s Achilles’ heel but James’s foot. Only ancient names that end with an s do not employ a possessive form of ‘s. All modern names do. One way to avoid the confusion is to rearrange the wording: the heel of Achilles but the foot of James. Yes, it adds words, and sounds a little stuffy, but the confusion of the possessive form is gone. (Note: While not all style guides agree, most do.)
Whenever using acronyms in writing, non-fiction or fiction, one needs to define what they mean—normally. In fictional writing, if you mention the FBI, most will accept that this stands for the Federal Bureau of Investigation. But that SIFFY… No one will guess that it stands for So It’s Fast and Furious Youth.
Phrases like “sit down” and “stood up” have redundancy built in. Down is the only direction one can sit (unless you’re in space) and there is no other way to stand except up. However, Jill can sit next to Jack, but she’s more likely to tumble after him.
The word gray, or grey, is one word where both forms are accepted by both a US and UK English spellchecker. So which is it? An easy way to remember: GrAy is for American English, and GrEy is for English English. There will be places that will prefer one form over the other. However, if in doubt, that simple rule will help.