Spelling can be a source of frustration for both parents and child. A spelling program should be teaching students spelling patterns and not assigning vocabulary words as their spelling words.
With that being said, here are two resources you may want to explore. The first one is for younger children (ages 4/5 - possibly 10). It is called Secret Stories. This is a program that was developed by a brain researcher and educator. She has created "secret stories" to help students understand phonics. The reason I mention this program, not only because I think it is a brilliant approach to learning phonics, it starts with the basic which so many of our children don't get or can't remember or apply when it comes to spelling. http://thesecretstories.com/
the second resource is a book called Words Their Way by Donal Bear. It explains the developmental approach to spelling. It provides many activities that can be done at home, list upon lists of words, and then shows students the application of spelling in their own writing. You can find this book in most large books stores or public libraries - so you can check it out for yourself. And it is always available on Amazon. http://www.amazon.com/Words-Their-Way-Vocabulary-Instruction/dp/013021339X
Once your child understands the spelling pattern behind the words, he should be more successfully.
If you have more specifics you'd like to share with us, please repost your question.
What I do with my nephew is that I make him write out each word out about 10 times. After I give him a quiz on how to spell them. Whatever word he gets incorrect he has to write it 20 times. If you do this daily he'll get it. Repetition has worked for us. Boring and time consuming for the adult but it has seemed to work. I hope this could help you.
My students struggle with spelling and what I've found that they like is sensory spelling. Use shaving cream on the kitchen table or counter and have him write out the spelling words in the shaving cream with his finger. Make sure he says the letters as he's writing them. You could also use sand to trace out the letters. Another one would be to take construction paper and crayons. Write the word once then trace over it using a different crayon color from the rainbow. Also, I like to use a cookie sheet and alphabet magnets. I always make it a contest in my classroom of who can spell the word correctly the fastest. You can also just practice using the magnets to practice spelling. Hope this helps!