there is not really a 'spell' for a wish, but there is a ritual. here's the steps:
1. cast a full spiritual circle properly
2. find three other people to do the spell with you because you need four to call the corners- north, east, south and west
3. buy a book called 'everything you need to know about witchcraft' and it will explain how you set up a ritual.
4. learn all the lines for the ritual from the book.
5. personalise them into a wish ritual with your own words.
if you need to know anything else, ask me, i am a witch.