I agree, don't make a big deal out of the jump. It's really just a slightly elevated trot/ canter pole. Make sure your horse is going forward and maintain its rythm, this will keep it from trying to run out or refuse. Basically I think of it as 'attacking the jump,' and this works well with most school horses. Whatever you do, do NOT look down or at the ground, pick a specific focal point (ie that branch on that tree,) and keep your eyes on it. Make sure your heels are down, give your horse his head, and hold on to the mane or neck strap so you don't get too left behind. Don't immediately sit own after the jump, stand up for a few strides to regain control, and then keep going and finish your line :)
I know it seems like a lot to think about, but you'll quickly get the hang of it! Jumping is really fun and challengeing at first, but it soon gets easier.