Are all your photos organized? Are they all in one place? How are they stored? Are they in proper containers? Labeled?
Consider gathering them together first. Then consider categorizing them. This can be done in many ways, by person, chronologically, events, holidays, vacations, etc. Make sure you have enough space to spread out the categories. Lastly, consider good storage and ways to make the project easy to build on as it is ongoing.
Check out our new system for organizing photos.