I googled this for you and found several websites that offer great suggestions, I've added the link to Martha Stewart in my answer and provided several other sites for alternative options that I've listed in the source box, hope they help !
This is an article from Martha Stewart, I'm sure she won't steer you wrong:
This is the website for Martha's tip:
"Cover cut raw potatoes with water to stop them from turning brown. You can prepare them the night before and still have creamy white potatoes the next day.
Start by scrubbing potatoes under cool running water to remove dirt; prepare as directed in recipe. Place in a bowl, and cover with cold water by 1 inch. Refrigerate; potatoes will keep up to overnight.
First Published: May 2006 "
Good Luck !