Do as much as possible in advance. Plan. Schedule content. Obtain help.
Consider creating a Facebook event or a Google+ event. This gives the event its own space on social.
Market your social networks and the hashtag on print materials, such as posters, programs, business cards, postcards, etc. Also, create digital versions of these print pieces to share via social.
Schedule what can be scheduled! You will be busy - save yourself the trouble.
To engage on social, many of your participants will need good, strong WiFi. Make sure they know how to access WiFi and a password if necessary.
Figure out your camera-to-social situation. Also, bring your charger or an external battery pack.
Set up your analytics before the event, including any tools that can track posts using the hashtag.
Shorten links you know you will use. Create bit.ly bundles when necessary.
Create Twitter lists with the handles of all the speakers, influencers, and even participants.