When can you exclude 'that' from a sentence?
Often that can be removed from a sentence without affecting the overall meaning, especially when it has been used with a conditional. e.g. She told me that I could go to the party vs. She told me I could go to the party.
Sometimes, however, you can change or lose the meaning by removing that. e.g. I heard that you snore = Person A snores, and Person B has told Person C about it. I heard you snore = Person A snores and Person B has heard them doing it.
Consider whether your use of 'that' is necessary for understanding time, object or person. If not, you can probably cut it.