Even though semicolons and colons look similar and have similar names, they have different functions.
Colons indicate that a list is coming up. However, you can only use a colon after an independent clause.
Wrong: My favourite punctuation marks are: semicolons, colons, and ellipses.
Right: I have three favorite punctuation marks: semicolons, colons, and ellipses.
Wrong: My employees must have:
Right: My employees must have the following skills:
If you’re unsure about about whether or not you can use a colon, check if the part before the colon makes sense by itself (i.e. is an independent clause).
If you’ve placed your colon correctly, you can replace it with “namely”.
Chloe: What advice do you have for new bloggers?
Brian: Write for you target audience.
Here colons and semicolons are similar. You can replace a semicolon with a colon if the second independent clause explains or illustrates the previous one. You can choose whether or not to capitalize the second independent clause.
I am so proud of Aubrey: she practiced for years to win the competition.
I am so proud of Aubrey: She practiced for years to win the competition.