Weather=we+at+her so we would probably make up a story like:

WE looked AT HER weather balloon.

Just something weird that will stick in DD's mind.

Head=he+ad So I would have DD make up a story about that. Having the child come up with the spelling story works much better than me coming up with something for her to memorize.

For "igh" I have talked about how those letters were orginally pronounced. So whenever she sees the word "knight" she also thinks "k-nig-h-t".