Any space craft trying to reach to any planet including earth, it is pulled by planet’s gravitational force. Naturally it accelerates the speed of the rocket and the rocket tends to crash down to the surface. This is “The fact” for any rocket landing on any planet as well as earth. Hence landing on earth is very similar to landing on any other planet. However, scientist developed many techniques so that the rocket can nullify a part of gravitation pull and survive the impact of landing.
Usually there are 2 types of landing. In hard landing, rocket creates significant impact on the surface of the earth but still survive. In soft landing, rocket lands on the surface at with almost safe speed and then impact is significantly low. There are no of techniques through which these types of landing can be done by reducing the speed of rocket by artificially created force acting just opposite to the direction of gravity. Some these are (a) parachute landing, (b) air bag landing, (c) full throttle landing etc.
You can check out the history of landing space crafts in the link below, http://en.wikipedia.org/wiki/List_of_landings_on_extraterrestrial_bodies