I'm currently using the approach of teaching alphabet by alphabet and I incorporate the use of collages for the teaching of every letter as I believe that it is of utmost importance that the child is exposed to the vocabulary words beginning with the letter she's being introduced to.
Personally, I find that there is little to boast about should a child be able to rattle off the whole string of alphabets in sequence but is equipped with a pathetic store of vocabulary.
Apart from collages, I also try to come up with other learning aids to reinforce the learning of the alphabet and I sometimes infuse this with teaching Math. Afterall, it's good to use the inter-disciplinary approach to teaching these days! :)
