I think your marketing techniques are better than ours (h/w our uni regulates certain areas in which we can advertise). What we did was have a whole week of different activities. We even painted on walls and wrote chalk on the floor and posted up signs everywhere.
The most important this is to be organised and get planning pretty early on. Our Activities were as follows (P.S the society has been doing this every year for the past 5-6 years with different themes each year):
Monday
Free Barbeque - While were handing out food we also give free islamic material aswell
Tuesday
Well we did a Debate titled "Islam or Liberalism which is the way forward". This was really successful and a lot of non-muslims showed up.
Wednesday
Bake Sale- we ask the muslim students to make food and we sell it in the agora (were everybody gathers it has shops and stuff). Every year we donate part of the money to different organisations. Last year it was for Afia siddique foundation and this year its for the Deaf Muslim Support Network
Thurday
Prayer room Open day- Usually we dont get as much people but this year cause i felt like volunteering this year i suggested that the make the prayer room look as beautiful outside as it is inside and it worked. We had a lot of people coming
Friday
Lecture: What is the purpose of life?
The speaker was pretty good although i wasn't too happy with the venue i would have preferred it to be in the city (more people come). Yeah but alhamdulilah overall it was great