Dictations go in and out of fashion. But who cares about fashion? A traditional dictation can be a nightmare for someone who can't spell well. They listen, they write what they hear and then they are told that they got it wrong! But this is when dictations are used as a test.
Here's a way to use dictations to really help learners improve their spelling.
1. Lead in to the topic of the text - get the learners interested in it.
2. Ask a couple of general questions about the text and then read it aloud to the learners. Check they understand by answering the questions.
3. Now give the text to the learners and read it aloud again so they can follow.
4. Tell learners you are going to dictate this to them in a few minutes. First they underline any words they think they will have trouble spelling. Allow them time to learn these words. Use methods from http://thespellingblog.blogspot.com/2009/01/seeing-spelling.html or Look Say Cover Write and Check.
5. Now they cover the text and put away any papers with the spellings on and you give the dictation in the normal way. (Read a small meaningful chunk out loud, now say it twice silently to yourself while students write, then aloud again, then twice to yourself again - this seems to make the pace about right for most people, but allow more time if necessary).
6. Now check the dictations or get learners to check against the original text. But be aware that people who can't spell well often can't see their mistakes either. Any words which have been misspelt should be listed (correctly) and learnt before the next lesson.
If learners have made a lot of spelling errors, then this suggests the error was ours! Choose an easier text. Aim for 90% success and then gradually increase the difficulty. Get a learner to do this every day for a month and you'll really see a difference in their spelling.
I learnt this technique from ex-colleague and now successful ELT author, Gillie Cunningham
Let me know how it goes.