How do missiles steer (mainly air to surface)?
Take a look at the following image. What do you see?

The Fins, Wings, and Canards, as seen in the diagram, work in a similar fashion to rudders/elevators/ailerons to develop drag to yaw/pitch/roll respectively.
Fins: Most missiles use tail fins which give extreme maneuverability and high angles of attack. Often they are fitted with wings to give extra lift and improved range. Maverick, Harpoon, AIM-9X Sidewinder are good examples of tail fin controlled missiles.

Seen above: Grid fins
Wings: Generally, wings play the same role as for an aeroplane by providing lift, and are the oldest type of control surface. Moreover, wings cannot work independently and in most cases are used as vortex generators to improve the efficiency of the fins. In addition, they are mostly used in subsonic cruise missiles like Tomahawk and Sparrow AIM-7. The problem is that the wings must be long enough to produce necessary lift.

Canards: They work more effectively with great maneuverability on low angle of attack, and work the same way as fins. However, located near to the nose of a missile, canards can cause a missile to stall at high angles of attack, which limits them to short range. Almost all smart bombs and laser-guided missiles use canards.
Furthermore, the split canard is a modern development (found in missiles like Python-4 and AA-11) which uses two canards, one of which is fixed, and the second is located just behind the first set and is movable. The role of the fixed canard is to develop high power vortices for the movable canards, for better performance at high angle of attack.
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