What are incorrect examples of colons?

Excuse me, could you please clarify for me what constitutes incorrect examples of using colons in writing? I'm a bit confused about the proper usage and would appreciate some guidance on what to avoid. For instance, are there any scenarios where using a colon to introduce a list or explanation is inappropriate? Or are there any common mistakes people make when employing colons in their sentences? I'd really appreciate your insights on this matter.