Are you looking for a technical co-founder or a co-founder in the marketing / business fields?

I think if the idea is a good one, and you don´t have a co-founder yet, try to get some cash and hire one or more freelancer instead of giving away 50% of your company for some days / weeks of work. It depends on your strategiy, the idea, the potential, cashflow planning,...

I would suggest that you do a business model / business plan, at least a small one, first, so that you have something to show to potential investors / co-founders.