It's important to remember that neither Kepler nor Tycho had any physical explanation for the planets' orbital behaviors. Kepler merely described the patterns he found in Tycho's data. These laws apply not only to planetary orbits, but also to the orbits of all objects in our solar system - moons, the individual particles that comprise planetary rings, comets, asteroids, and the like. The Laws These three laws were based primarily on Tycho's measurements of the orbit of the planet Mars that, because of its proximity to the earth and its relative proximity to the sun, completes a full circuit of our sky in roughly 2 years. This gave Tycho the chance to accumulate many orbits' worth of data over several decades.
All planetary orbits are ellipses, with the sun at one focus of the ellipse.
In its individual orbit, the closer a planet happens to be to the sun, the faster its orbital speed, and vice versa. Since all planetary orbits are ellipses, there are always times when the planet is closer to the sun, and times when it's farther away. When it's closest, its orbital speed at that moment is fastest of all, and when it's farthest away, its orbital speed at that moment is slowest of all. Comparing all the planets, the greater a planet's average distance from the sun, the slower its average orbital speed. Here we are comparing one planet to another, and the actual shape of the orbit really doesn't matter.