Memorable branding is something hackers and sponsors come to associate your hackathon with. It’s essential to have a consistent strategy in this regard. It’s best to have someone with good design sense on your team define the primary design guidelines for the hackathon and ensure that it’s reflected in the logo, posters, and other creatives.
Make sure you design graphics for banners (include sponsor logos in them as per tier deliverables) and standees (some may be needed to define hacking zones, food zones, etc.) to be kept at various locations throughout the venue.
Hackathon schwag (T-Shirts, Stickers, and other goodies) are something hackers have come to expect at all hackathons they attend. Quirky designs and copy makes the schwag more memorable for hackers and encourages them to use them even after the event is over. This, in turn, leads to better brand recognition for your hackathon.