Learning the alphabet is a sequencing activity, and one that can be surprisingly difficult as it is 26 things in a row. Typically, it is taught in a sing song to aid the children in learning it. And while I am a big fan of using songs and music when teaching, the problem with the alphabet song is that many children don't connect the words (a, b, c, d, etc.) to the symbols they represent. Additionally, when the alphabet is learned in one long song, it usually means that for a child to know what letter "comes next" they typically need to start at /a/ to figure it out. This is time consuming and really means that they don't know the alphabet sequence very well at all.
 
Accordingly, I always teach the alphabet in four segments: a-g, h-m, n-t, and u-z, one at a time, sequentially, cumulatively and in a fun and engaging way.