How about organisation-specific discounts, so you can target likely individuals without others getting miffed? i.e. for Microsoft resellers. You can make it appear even more exclusive by offering a restricted number of tickets.
Or rather than discount, perhaps just invest a bit more in marketing and run a Facebook ad campaign, including retargeting those who have expressed interest but not converted.
You could also incentivise purchase by offering some kind of free download - maybe you have a speaker who has written an ebook you could partner with or something?
Finally, consider setting up an affiliate/referral programme and let other people do the selling for you. Good luck!