Understand your target audience
What companies can you help? What problems do you solve? Who can afford your solutions?

The answers to these questions can help you to clearly understand which groups of companies are potentially interesting for you, in other words, who would be more likely to purchase your solutions.
For companies, which have an extensive portfolio of work, it's always easier to define specific target groups since they have already gained valuable experience in specific domains. In case, you just started your business and your expertise is quite diversified, without any specific focus, you can consider several niches in which you'd like to start. There is the opinion that companies with a narrow specialization are more attractive for potential clients than companies which act as a one-stop-shop. It can be explained by the direct focus on their particular area of expertise compared to other companies who are willing to help you with everything at once.

The final goal of this stage is to create an ideal client profile (ICP) that describes the type of company your solution could benefit. Information such as: industry, geography, size (annual revenue, number of employees, number of offices), and budget can be useful in identifying your ICP.
Who are the relevant decision makers?
The most common scenario is when CEOs become the main targets of sales managers from all over the world, and they are literally stuck trying to distinguish really important emails from sales pitches. It's not surprising, CEOs are usually in charge of making all the serious decisions within a company, and they still receive tons of emails throughout the day, so it can be quite challenging to grab their attention. On the flip side, depending on your specific offering, it's better to consider a decision maker from other relevant departments like: Marketing, Business Development, Engineering, Operations etc.
For example, if your product is a testing software, the CTO or VP of Engineering will be more likely to consider it than a Managing Director, who possibly wouldn't have an engineering background and couldn't properly assess the real advantage of your offering.