Excellent question, there's a couple factors that must be first addressed to give you the most effective answer:
-Are the 75 participants loyal, returning guests or are they generally new faces?
-Do you offer upsells at this event? This opens the potential to reduce ticket door revenue to increase profit from back room sales?
-Do the events revolve around themes? This would allow you to generate consistent attendance and have guests bring friends to also implement this bi-weekly theme.
As a first step, I would try to get a very good understanding of these things from the people who attend one or more of your next three events: what they like somewhat, what they like strongly, what they don't like somewhat, and what they hate about the event. Basically a 2*2 matrix of like-dislike on one axis, and weak-strong on the other axis.
Some strategies may come out directly from building this understanding.
A couple of thoughts:
First, consider a smaller venue - say for about 80-85 people. This will make the event seem "bigger" to new attendees and help you generate some buzz about it being well-attended. A large, empty space that's half-full creates the opposite impression - even though 75 people is a really decent turn-out.
Second, I'd put the question of how to increase turnout to your attendees via a web survey asking whether they would recommend the event to other entrepreneurs that they know and why/why not. This gives you a net-promoter score that you can use to gain some insights on what folks find most valuable which in turn can be used to target new attendees.
Great question, by-the-way. Good luck!
The biggest thing about filling any workshop or conference is to have a great connection with your community. If you don't already have a newsletter built for the event, you should.
You should be encouraging people to promote. One Facebook, on Twitter, etc. Spending and doing a careful targeted ad on Facebook even for just $20 helps.
Make sure to reach out to local businesses or Internet companies that are relevant to your event to see if you can get sponsorship for them. They are more than likely to tell their people about your event too.
Having a discounted coupon code is definitely nice to have.
Make sure your topics and speaker or speakers are interesting.
Approach bloggers relevant to your event's niche and let them know about the event. It might help even if they were closer to your venue, at within 150 miles of it.
Go to Meetup.com and look for local area groups, especially similar to your niche, join, and ask the organizers if it is cool to post your event. It would be courteous if you'd at least attend their events, which are normally free (minus gas to get there and possibly food cost.)
It is important to ensure you communicate the value of your event and what people will get from their investment. Then you have to over deliver. Next, you have advertising your event more than you probably want to--especially on social media. You have to figure out when your audience is online and make sure you're online promoting your event while they are there. For most entrepreneurs, early mornings and late evening seems to be their time. Hope this helps!
When I support organisations live events, I always start with some questions around their objectives. I'd start by asking why you are thinking about "doubling attendance"? Is this really the best objective to be chasing? I often find the best events, from a supplier and an attendee perspective, are about quaility and not quantity.
There are a variety of ways to grow your numbers. My approach typically yields 100-150 ppl per month with numbers ballooning to 300-500 when I "step it up."
The secret to my consistent larger numbers each month comes down to one thing - my monthly email marketing sequence.
Sure there are other things you can do.
Use different platforms to attract ppl - like Meetup etc.
You can implement a "Bring a Buddy" initiative - this doubles your numbers quickly if they do.
You can implement door prizes, giveaways and other interactive contests that you promote in advance to draw larger numbers.
But in the end ... it all comes down to how you market and message each month. I can't easily explain the monthly cycle in this answer box, but I'm happy to shoot you a free copy of my best selling book MEETUPOLOGY that explains much of what I did (and still do) to make the numbers of which you speak.
Let me know. And naturally I'd be honoured to speak with you directly too.
Writer & Digital Coach