If you've ever compared colleges then one of the statistics you probably looked at was the faculty to student ratio. The thought of course is that smaller classes provide a better atmosphere for learning. The same can be said for small events, especially if you've ever sat in the back row of a large conference!
The key with planning smaller events is to play to their strengths and not make them into something they aren't. Don't push all your attendees into a room and preach to them all day when you can add interactive elements like team challenges, networking functions and answer sessions.
Some elements of event planning are the same for any size event (dates, times, etc.) but planners have more room to get creative with small events. As always, the best approach is to analyze everything from an attendee perspective.
Also Read: The Small Event Planning Checklist