Commas with Introductory Clauses

Use a comma after introductory infintive clauses.

Example: To improve her English, she practised on ego4u every day.

Use a comma after introductory prepositional clauses.

Example: Before he went to New York, he had spent a year in Australia.

Use a comma after introductory participle clauses.

Example: Having said this, he left the room.

Note: In short introductory sentences, the comma is optional and can be dropped.