Be real and let your guard down. Sure, be good at your job, but also be personable and know how to build rapport and make good conversations with people.
Find a group of people to hang out with which you can brainstorm with - not just your immediate team. If you're in marketing, then join a marketing meet up. If you're a developer, find a developer meetup you can attend. In the rare chance Meetup doesn't have you covered - set up our own meetup group. In doing this, you'll get to see what other challenges people in your industry are facing, and also be able to share your own expertise.
Sometimes the best relationships are built after business hours or out of the office. Treat networking like college - don't think you have to do just talk business and do work and keep it all professional. Take your client out now and then, do extra curricular activities and socialize.
Manage the chaos of a busy week - don't let it manage you. Theres a big difference in working in your business, and working on your business.
Get out of your comfort zone.