A good article from a couple of months back discussing the importance of maintaining relationships. As wiser folks than me have pointed out, always best to do this in advance of needing to lean on them.
The article highlights the need for your humility in this process and putting aside personal dislikes. Though they focus on the relationship with your boss, I think I’d be more keen to engage in a 360 degree strategy.
“…[I]dentify the most critical relationships, those individuals crucial to both your success and the success of the business, and nurture those relationships. This entails asking people’s opinions, even if you don’t think their views are likely to be helpful. It means telling people what you are doing and why—sharing information with them so they never feel left out. Serving relationships means going to visit people in their offices, not yours, and in countless other ways showing others that you value them, their experience, and their expertise.”