A good cofounder is not an easy person to locate. Often times the wrong choice can lead to your startup's untimely demise and there are plenty of wrong choices IMO.

I've personally found it easier to contract the work out and then if one of the contractors proves to be a great asset and we work well together I can then proceed in making them a cofounder or giving them some equity.

There are 2 things you absolutely need to know about this person before you move forward in making them a cofounder:

1. Are they good at what they do?

2. Can you trust them and work well together with them?

It is extremely hard to find a co-founder. And not easy to trust them too. If you don't know anyone, it's probably not the best idea to look for one. (I wouldn't) Again, this also depends on what skills you bring to the table, and what else is needed which you can't provide. There are some things which can be handled by employees, and they are certain things which should be handled by a "founder".