Yes, it worked. It's how I started. It's the least efficient form of marketing, as you immediately start with a negotiation disadvantage. Ideally, you want the client to approach you first.

It's still a little better than approaching people who post ads looking for freelancers, because they get flooded with offers and are often inexperienced enough to take the cheapest.

There's a methodology: Keep it short. Show, don't tell. Approach people near the top first, not from the bottom (e.g. email the CEO instead of customer service). And follow up.