need help...car show tomorrow...electrical issue?

If it starts every time by jumping it at the relay, you've eliminated the starter, battery, and cables as the problem. If the starter is not making a sound, it's going to be the relay, ignition switch, bulkhead connector, neutral safety switch, or somewhere in the wiring to and from those components. If the starter is working every time and the engine is just not starting, it could be somewhere in the ignition system.