Hi X Mode,
Casiopea is absolutely correct in saying that the phonics method is the best way to help your student with her spelling.
It's a good idea to work with groups of words that sound the same. In that way, she'll learn the concept (rather than just individual words). Say for instance you pick words that end in -ck (block, clock, sock etc.), she will learn that all short accentuated words ending in with a "C" sound, is written with a -ck at the end. Later she'll instinctively apply this rule to other words too.
I think
www.spellingfun.com is an excellent site to use. They have a full spelling program based on phonics.
If she does the "free flight test", you will know exactly where to start. She'll love it. The program is games based. It has sound and the first exercises explains the meanings of the words. There's lots of great tips and tools too.
I think you're giving her a wonderful gift. Learning how to communitace with confidence is one of the best skills to have.
Keep up the awesome work!
Charine