Carefree means not having any worries.  It is not to be confused with careless which describes acting without due considereation or care.  It is the opposite of careful.  There is a wonderful example of its use in Oscar Wilde’s play, The Importance of Being Earnest:

To lose one parent, Mr Worthing, may be regarded as a misfortune; to lose both looks like carelessness.

Oscar Wilde gave his character outrageous lines, but they are funny; the speaker looks ridiculous, equating being orphaned to losing a personal belonging.

Slapdash is another word for doing something quickly and without care.  Whether it relates to careless handwriting or pebbledashing a wall I do not know.

With reference to is a phrase putting something in context.  Business letters used to be very formal, with phrases such as I refer to your letter of… Nowadays email has its own etiquette.

No magic formula implies that something will take time.

Hackneyed describes an over-used phrase.  Hackney is a district of London.  There used to be a form of horse-drawn transport known as a hackney-carriage.  These were named after the size of the horse pulling them and were used like taxis.

Words fail me!  The speaker is too shocked to say anything.

A few well chosen words is rather a cliché.

A word of warning may help prevent a disaster.

String a few words together means write something.  Someone with the ability to do this is literate.  It is often used as a joke about highly educated people especially if they are verbose.

Break one’s word means break a promise.

My word is my bond or an Englishman’s word is his bond used to be popular expressions.  No written guarantee was needed if someone had made a promise.

One word from me and they do just as they please is frequently heard from someone with small children in their care.

They might add,I can say something until I am blue in the face and it doesn’t any difference”.

A way with words is the ability to speak or write influentially.

A pen-pusher is someone whose job involves sitting at a desk and writing.

Jot down means make a quick note on paper.

Not one jot or tittle refers to details of writing – a jot is the dot over a lower-case I, a tittle is the dash across a lower-case T.

The King James Version of the Bible used this phrase in Matthew 5:18  For verily I say unto you, Till heaven and earth pass, one jot or one tittle shall in no wise pass from the law, until all be fulfilled.

Here wise means way.  Click the link for a modern version in context.  Matthew 5:17-20