Constructive/Divergent Tectonic Plate Boundaries:
A Constructive or Divergent tectonic plate boundary is one where two of the Earths plates are moving away from each other.
Molten magma from within the Earths mantle rises up through the gap created in the Earths crust, this cools forming sheild volcanos and island arcs (new land).
Only Oceanic Plates can form Constructive/Divergent Plate Boundaries.
Destructive/Convergent Tectonic Plate Boundaries:
A Destructive or Convergent tectonic plate boundary is one where two of the Earths plates are moving towards each other.
If one of the plates is Oceanic and the other is Continental then the heavier Oceanic plate will sink and subduct under the Continental plate. The plate will sink into the subduction zone where the material is melted by the heat from the mantle, this hot magma rises to the crust and flows out through cracks in the crust. The ash and larva produced cools to form layers which build up to make a Composite volcano.
Also as the Oceanic plate is subducting under it can get stuck to the Continental plate, this causes masses of tension to build up as both plates are now unable to move. After a while this is released and the Continental plate springs back up. The release of tension causes Earthquakes and Tsunami's by sending out Seismic waves.
But if both plates are Continental/Oceanic are are therefore the same mass, then they will push together and crumple to form fold mountains.
Conservative/Transform Tectonic Plate Boundaries:
A Conservative or Transform tectonic plate boundary is one where either two plates are sliding past each other (going in opposite directions) or two plates are moving together in the same direction but at different speeds.
If the two plates stick then tension will build up as they both try to move, and after a while, they will become unstuck releasing the tension and seismic waves which will cause an earthquake or a tsunami. Also it will cause both plates to suddenly shift forwards several metres.