Advertising a symposium A group of PhD students and young researchers (where I belong) is preparing a symposium, a single day meeting, for other young researchers, PhD, master and students.

I don't have any previous experience with advertising this kind of events and I haven't received other advertisement, to an event similar to this one, than a place and a date with a link for more info. However, this was from a better known organization (and I get to know this organization through a friend) and our organization is not well known so I doubt this way would work to attract new people.

Which is the best way to increase registrations to the symposium? What information would you like to know before going for a registration or looking for more information?

Some important information I thought to include in a leaflet/ad:


Place, dates, duration (done)
Where to register and how much does it cost (done)
Key speakers (At the moment we don't have confirmation of all the invited speakers)
Sponsors and support (done)
...


There's a similar question question for a similar event, but I am in charge of advertising.
Some suggestions for improving participation:


Recruit two to three faculty members to serve on a panel to judge presentations. The top three (or four or five) presentations receive prizes. Include this on the flyer.
Every participant gets a certificate of participation.
Announce a recognized name as a keynote speaker, if possible. Not a big deal, if it's not possible.


Then, mail the flyer to the graduate program directors (of the relevant departments) at the nearby universities and ask them to encourage their students to participate in the symposium. Also contact the graduate student organizations at these universities.