I mean hiring here not only in the traditional sense of hiring employees fro your company. It's important to be careful in "hiring"/selecting right partners and suppliers because all this influences your business from money and image side.
I would say from my experience it's extremely important to be wise and careful and attentive and all this together plus more when getting other people involved. If you are lucky enough they can bring success or at least not damage what you have created. Those people will spread your elevator speech as well, support and be part of common thing.
Especially in a small size company like every step matters same every person involved matters. try to get clear goals in front of the person you try to involve in what you do and also clear expectations on what you can get from this person.
Try to see clearly for yourself what this person/other business can bring you as value and in a small business try to make sure control remains in your hands.