Well, a bit more information (or a link to the campaign) would be helpful. Effective marketing/branding is easier to achieve if you already located some budget (probably your own money) towards this purpose. I can't really comment specific on your situation (due to lack of information), but here are some really general tips:
- Make sure to use Twitter and proper hashtags (e.g. #screenshotsaturday)
- Join relevant groups on Facebook (this group for example has nearly 20.000 members that are interested in indie games and crowd funding, there are tons more:
https://www.facebook.com/groups/227592780726252/)
- Have a proper demo ready and a good trailer/announcement trailer. A trailer has more impact compared to screenshots, if done well.
- Interesting milestones for your campaign (more content when certain goals are achieved is one example)
- Research press that are writing about Kickstarter campaigns and contact them. (Make sure you have a press release)
- If you want to get creative you can do a lot with Fiverr to help your campaign (
http://fiverr.com/)