Well, the first thing you do is you make pre-game an event, and tie the even with the market you are targeting. So, if you are appealing to teenage fans, you bring in a band that appeals to them and say "Concert here with purchase of ticket." as a general rule, you want a band that caters to the segment you are targeting, but doesn't alienate your other markets. I know many older folks didn't appreciate the rap show during the east semi-final last year (and maybe they feel that segment is more important) but a band with more universal appeal, and not necessarily a high cost helps things out. If you are targeting families, you offer low cost options for young fans and an inflatable play area at one of the stadium gates. If you are targeting older fans, you continue to have your retro days.
Second, you must have signage. Look at TravelPatB's photo. There is not a single Argo logo in that entire plaza. Sure, it's a Jays game...but that entire strip is the exact same during an Argo game. You NEED to get your own signage. When you are seeing more ads for the Marlies then the Argos on the walk to the dome, there is a problem.
Third, you need to build the game at the grassroots level, and this is incredibly hard in Toronto and even harder when the Varisty Blues and York U. both have lame duck teams, and have for ages. Not sure how much though you can do to build it up though, but given minor football 50/50 draws instead of the Rotary Club seems like a better idea.
Four, you adjust your ticket prices. A packed house is a good atmosphere, and half empty house kills the atmosphere. When you are playing out of a 50,000 seat stadium, charging 50+ for a silver ticket is absurd. Now that being said, this is a problem in itself as you can't price yourself out of the market either.
Five, you work with local businesses to advertise and ship people in. A couple of Argonaut coasters given to a bar, or a light fixture showing support for the team. You give local businesses discounted tickets so they can have the pre-game party make their money and then ship fans to the stadium.
That's just a few ideas, now sadly three of those five are directly linked to your stadium precient. Rogers probably won't allow a property party outside the stadium, they won't adjust the signage, and the venue is simply too large that if you got tickets down to the level they should be at to pack the place, you'd be losing your shirt.