If you're a player who doesn't yet know the tricks, you might find yourself frustrated with Chrono Trigger early on in the game, just after your first return from the Middle Ages. Once you arrive, King Guardia accuses you of kidnapping his lovely daughter—what, doesn't he know she has a rebellious streak?—and has you thrown in the old pokey. When you get to trial, the jury's really got it in for you, too; you can be found not guilty, but you're still going to end up with a guillotine date. That said, none of these things really matter in terms of plot, but if you want to find out how to get the positive outcome, read on.
What really trips people up is the fact that most of the conditions you have to meet to get "not guilty" are things that must be done before you even leave the Millenial Fair. Here they are in order of how you'd likely encounter them:
If you were successful in doing all of the above at the fair, when it actually comes time for the trial you're in good shape and most of the work has been done for you. The witnesses for the prosecution will not be very convincing! You'll still be interrogated on the stand, though, and will face three questions.
As mentioned above, you're going to jail to await execution even if you get all jurors to proclaim you innocent. The justice system of Guardia clearly needs some work. Once you get to your cell, though, you'll find a treat waiting for you: if you convinced every juror to find not guilty, you'll have seven Ethers in there; six jurors will get you five Ethers, five jurors will get you three, and if you get just four jurors you'll get a single item.
Once you're locked away, you have one more binary choice coming up. You can either sit and wait patiently for your execution and hope that maybe the Chancellor gets hit by a flying time machine before the time comes, or you can beat on the door of your cell until someone pays attention. If you do the former long enough, Lucca will come to the rescue, and make the path easier during your escape by both giving you an extra party member for the escape and by knocking out most of the enemies along the way. If you're a tough guy, though, you can rattle the gate and knock out the first guard yourself; this will give you more enemies to fight and only one party member for most of the escape sequence, but will give you a chance to win more Tonics from Guards.