Appellate courts review what the trial court decided. An argument raised for the first time on appeal is ordinarily forfeited.
Forfeiture and waiver are distinct. Forfeiture is the failure to timely assert a right; waiver is its intentional relinquishment. Forfeited claims may be reviewed for plain error in some contexts; waived ones are unreviewable.
Preserving an objection requires stating the specific ground. An objection on one basis does not preserve a different basis, which is how evidentiary points are most often lost.
Motions. A denied motion in limine may or may not preserve the issue depending on whether the ruling was definitive. A denied motion for judgment as a matter of law must generally be renewed after the verdict to preserve a sufficiency challenge.
Plain error in civil practice is available in some systems and requires error that is clear, affected substantial rights, and seriously affects the fairness or integrity of the proceedings. It is granted rarely.
Purely legal questions on undisputed facts, and questions of jurisdiction, may be raised for the first time on appeal at the court’s discretion.
Practical instruction for trial counsel. Make the record contemporaneously, state grounds specifically, obtain rulings rather than leaving objections pending, and make offers of proof. Ten seconds at trial preserves an issue that cannot be created later.