When these simple punctuation marks are not used properly, it makes a significant, negative impression on the reader. We all make mistakes when writing (and life), but we all can work very hard to be aware of how and why we use the common punctuation marks.
ESSENTIAL PUNCTUATION
The old way of learning grammar may not be working. As you strive to learn this punctuation, consider using Bloom's Taxonomy (see UNDERSTAND EVERYTHING). Start by looking at the actual construction of the punctuation marks. Their design gives a significant clue of how each is supposed to work in formal or professional writing.
The PERIOD - . - It is a dot. It is a stop sign. It is the end of the sentence. It means stop. All sentences must have an end mark which stops the sentence.
The period is the most common. Even the EXCLAMATION MARK ! and the QUESTION MARK ? still use a period in their construction, which means stop.
The COMMA - , - It is a period with a tail, or an anchor, or a wall. It is used to separate only.
The SEMICOLON - ; - It is a period stacked on top of a comma. If the period means stop, and the comma is for separation, the semicolon can only mean “stop and separate.”
The COLON - : - it is a period stacked on a period. It means stop but that the information coming next is also very important and related to the previous information.