Putting it out there

Day three of having sent my new book out into the big wide (and often well hidden) world of digital publishing. So many questions about marketing and promotion: How do you make it more visible? How do you tweet effectively? Should I try physical posters locally?
I had a nice flurry of congratulations and "likes" across facebook from friends and family - but how to get it further? I'd like it if I were able to use the monster machine that is my workplace; a university should have something useful help promote don't you think? But short of sending a university-wide e-mail advertising my untested and virgin first novel, I can't think of anything that might help. Of course you also have to think about things like how often do you actually look at staff noticeboards in work? And even if you do, just how often do you rip that little tab off the advert for a cheap sofa, or note down the number of that fitness instructor promising SAS like results on your chubby midriff?
No, I'm not sure an A4 poster, no matter how lovingly and cleverly crafted it is, is going to have much of an impact. But how else do you get seen and heard amongst the (as of five minutes ago) 16,000 other kindle books beating me on Amazon?