Think of LinkedIn as similar to SEO. It's a marathon, not a sprint. You're growing an audience on a social platform who will slowly become familiar with you as the expert in the industry. If you're adding value regularly, people will comment, ask questions and this is where your lead-funnel starts. You can't expect that you're going to get leads in the first 3-6 months of activity, but if you're applying best practices, you can have certainty that potential customers know exactly who you are and how you can help them.