Orbit is merely "bullet drop". Imagine firing a bullet parallel to the ground (mentally removing all air resistance to maintain velocity). The faster you fire that bullet, the farther away it hits the ground, right? Now imagine that you fire it fast enough that its downward curve due to gravity matches the curvature of the Earth. It would remain at a constant altitude above the ground and continue on around the globe - always falling due to gravity, but also always missing the Earth because of its forward speed.
That's orbit.
