I elicit a word that has the sound in it and write this above each phoneme to help students remember the sound.
Then I get the students to work out which sounds are short and which are long. For the long sounds I ask them what the symbols have in common (to teach them as early as possible that symbols/sounds with two dots and two symbols/sounds together - diphthongs - are long sounds).
We start putting the letters of the alphabet in columns underneath the phonemes as a class and then students work alone or in pairs to complete. Check together by reading down each column (also helps you to spot which letters of the alphabet cause your students problems).
The following lesson I often revise the seven phonemes by preparing a song gap-fill; the gaps are words that have the same sounds. We quickly revise the phonemes, writing an example word for each. Then I dictate the words needed to complete the song and students individually write them under the corresponding sound. They check together and we go over any problem words. Then we listen to the song and they complete the worksheet. For Pre-Intermediate/Intermediate students I've used Stand By Me (Ben E. King) and for Intermediate/Upper Intermediate students New York (U2) and I'm With You (Avril Lavigne).