Array Constrained Rotation

This entry will cover using the Array Modifier as well as a rotation Constraint to make a rotationally, symmetrical object, by editing only a small part of the mesh.  The example given is with creating a snowflake.

First step is to create an Empty.  You can use any type, i used a cone because the tutorial i watched did so.

Instance Along Curve

This entry covers the concept of duplicating a mesh (cube in this example) along the path of a curve.  This is a very useful animation ability when trying to grow a curvey line or path.  

To start off you'll need at add [SHIFT+A] a curve and a mesh (cube).  It is worth noting that the direction of the curve matters for this example.  To have the cube follow the path of the curve directly, you'll want to situate it at the beginning (curve arrows are pointing away from cube) of the curve.