The trouble with these is that they're easily confused and if you're not careful you'll confuse your child even more.
For words like: they're / their / there, your / you're, whose / who's, it's / its and where teach them in these blocks:
1. where / here / there
These are all words for place - and they're all spelled in the same pattern.
The best, basic way to learn spellings is:
Write out 5x, cover, test, check. Repeat the test after one hour, one day, then one week. If they're still getting it wrong, remind them of the rule, then they write out 5x again.
2. Then give your child this list:
my, our, your, their, his, her, its, whose is it? > ask them what these words have in common. If they still don't get it, you can write 'their friends', 'its face', 'his shoes'. The answer should be something like 'they all show something belongs'. They're also pronouns - and you can take the opportunity to show them the other pronouns: I, we, you, he, she, it, they > me, us, you, him, her, it, them.
3. They're and who's, you're and it's are all abbreviations.
For these, teach them to check. Is it short for They are, you are, who is, and it is? The apostrophe is in place of the missing letter.
4. For other confusables, try to make links.
e.g. threw > flew
I can hear the bear
loud > aloud
Let them draw pictures linking the word they do know to the word they don't. The visual memory is eight times stronger than the memory for words.
DON'T do more than 10-15 minutes at once;
DON'T learn more than five words at a time.
Give specific praise like 'well done, you got three out of five.'
DON'T demand 100%. Let them set their own targets. 'What do you think you could get next time?'
The good news is, you can do this with several children of different ages because younger children will benefit too.