This much we know!
Some children need very little support with their homework. In which case all you need to do is remind your child to do their homework, check that they've done their homework and that it is in their school bag on the day it needs handing in. In the case of spelling homework all you need to do is give them a spelling test to check that they have learnt their spellings. However, I'm assuming that you're reading this because your child needs more help than that
I taught in primary schools for 10 years before I had my family and now as a mum of a dyslexic daughter I think I know more than most about how to help learn spellings!
First of all have a look at all the spellings they've brought home to learn. Talk about the meanings of the words. Look for patterns in the words, have they all got the same endings or do they contain the same letter blends? Hopefully they will have a pattern to them, then you need to spend most of your time learning the pattern that they all contain, once that is learnt you can apply it to each of the words so you only need to listen for the initial letter sound. For example, if you have words like: heat, cheat, neat, meat, seat. You learn how to spell the eat part then it is quite easy to hear what sound you need to put in front of it to make each word.It is much less daunting to learn a pattern that can be applied to many words, than to have a huge list of 10 spellings that need to be learnt individually. My daughter can't see these patterns in words and needs them pointing out to her, so don't be surprised if your child can't see them straight away.
Look for words inside each of the spellings. If you can see a small word that you already know how to spell inside the bigger word, then that means there is less to learn! For example balloon has the word ball in it, house has the word us in it. Again, your child might not be able to see these words inside other words without your help.
Learning spellings by writing them down over and over again might work for some children, but certainly not for the vast majority! I get my daughter to "write" the word in the air using her whole arm as a "pencil", she writes it as big as she can! I also get my daughter to "write" her spellings onto her palm using the index finger of her other hand, it's very tickley, especially if I write on her palm with my finger! These are two ways of getting her to fix the spelling in her head, they might work for your child!
I often write a word we are struggling to learn on the window in eye liner or lip liner. I also write on the tiles beside the bath and on mirrors in lipstick. You could use Alphabetti Spaghetti but I don't find the capital letters particularly helpful for helping to visualise the spellings because that is not how she will write it.
I find that magnetic letters on a metal tray can be a good way of helping to fix the spelling in my daughter's head. I write the word in magnetic letters, then I mix it up, and she has to arrange the spelling correctly. By actually having to move and also to try to visualise it in her head it helps her to fix it in her mind.
Sandpaper letters are a good alternative to plastic letters because you can feel the letter which makes the experience of learning spellings a more tactile experience than it would normally be.
I combine written spelling tests with oral spelling tests because I think the combination of having to say the letters aloud as well as having to write the spelling down help to fix in her head the spellings that she is learning more effectively.