First gather all your pictures into one place. Keep only the photos that you will enjoy viewing over again, or may want to use some day in a slide show or photo book. Don't be afraid to throw away duplicates - remember they'll be digitized and you can always get copies. If some of your favorites are not in the best condition, keep them; the scanning process usually improves them.
Most people want them all in chronological order by year. But there may be certain occasions which you'll want to separate. If you think you'll want that once-in-a-lifetime trip to Europe where you can pull it out and look at it, keep it in a separate bundle within the correct year.
Bind them into bundles. It's a good idea to name your pictures, or attach keywords (a name, place, date) which will make it easier to find specific photos later. Use a 6B pencil to lightly write the information on the back of each photo. We will "title" your digital photos so you can easily search for them as needed.