Here is a cheatsheet poster for First Amendment freedom of expression issues in Constitutional Law. It is noted that alleged violations of protected speech will receive strict scrutiny, and that there are extra protections against prior restraint, overbreadth and vagueness. Permitted content restrictions include those on unprotected speech such as obscenity and incitement, and low-value speech, such as commercial speech and defamation. In addition, there are permitted restrictions on conduct, such as communicative conduct, and the time, place and manner that the expression takes place.
Credit/link to brendanconley.com.