What Tools or Strategies do you use for Sales Leads/Potential Customers?

To all my fellow Indiehackers out there, if you're involved with the sales side of your product, how do you find sales leads for potential customers? What tools do you use and what strategies do you implement?

Looking into building a service for finding sales leads and would love to hear what some of you use, what you like and dislike about it, and how you think it can improve.