Where to promote your productized service?

Hi everyone! I've recently done my first launch here and got some leads, which is cool! Where did you promote your productized service when you launched? I'm here thinking if I should invest a little bit in paid ads to target my ideal audience I have a clear picture of the ideal clients I work with as a freelance web dev. But often they find me, and it's difficult to understand where they hang out online. Often these are busy CEO / c suite people that seem not to spend much time in social networks