Once your grant has been funded, celebrate! Don't forget to thank the organization who's given you a grant. And make sure to post a comment here to let us all know you've succeeded!
If you've gotten turned down, don't despair. Many, many successful projects are turned down several times before they are funded. See if you can get any feedback from the organization, and then rework your grant and try again. Persistence is a key to getting funding.
Now comes the hard work -- doing your project. Good luck!