Thanks for letting us know how old she is.
I second Mamazita's use of Handwriting Without Tears. It does make use of a book and having to practice, but truly, at some point, she will have to do that. I'd start that at 6, but meanwhile, I like what Doc7287 says.
My kids did what is called "inventive spelling" in kinder and part of first grade. It keeps them from feeling "defeated", allowing them to not have to spell everything "just right". You work on the reading and spelling at the same time as the writing so that they slowly start to write sight words and vocab words with the right spelling. What you want is for them to initially learn to put their thoughts on paper without having to struggle to only think about the spelling.
By practicing the worksheets, they get used to making the letters so that they aren't struggling to remember how to make the letters at the same time they are dealing with putting words from their head onto paper, plus the spelling.
You know those free parenting magazines you find that have ads and articles? I saw a group class taught by an OT featuring Handwriting Without Tears for children who needed help learning to write. It was wonderful. Seeing other children do the same thing really does help kids stay on task and learn to do it. My son had a weakness in his writing hand, which is the reason I did it, BUT, it taught him the appropriate way to write (which makes writing easier than writing incorrectly) and it helped him learn the alphabet inside and out. I really believe that this is why my son ended up having no trouble learning to read.
If you could find one of these classes, you would find it much easier to teach her and she would really like it. Outside of that, try the other suggestions.