What's your general field? B2B, especially for big industries, tends to call for networking and possibly cold calls. Individual sales tends to call for advertising with a focus on high relevance sites. Social or two-sided markets (think credit card companies and users) tend to call for narrow early focus via outreach to online or physical communities. This simulates widespread use by creating a regionally high use space.
If you're in a specific field (e.g. online cello sales), do outreach to things like relevant forums and subreddits. You'll get targeted use which will provide quality feedback, hopefully. If it's a broad spectrum project, buy up relevant and cheap(ish) ads in several venues. Push use with some definable group that you can interact with directly, get emails via a newsletter, etc.
If you're in a specific field (e.g. online cello sales), do outreach to things like relevant forums and subreddits. You'll get targeted use which will provide quality feedback, hopefully. If it's a broad spectrum project, buy up relevant and cheap(ish) ads in several venues. Push use with some definable group that you can interact with directly, get emails via a newsletter, etc.