After working hard to gain the trust and commitment of a new client, an important step in your sales process should be to ask them for help in the future, after you've proven that you can deliver.
Recommendation: Every time you sell something build testimonials and introductions/referrals into your agreements. Here is some sample language.
'If satisfied with coaching services provided. Client agrees to provide a written testimonial for Coach's use in social media, on the Coach's website and in marketing materials. '
'When we deliver agreed upon products and services to client's satisfaction, client agrees to let 20 - 30 people know about their experience with us.'
'Once ROI goals have been met, client agrees to personally contact 10-20 peers to recommend they connect with us to explore how we might work together.'
There is nothing wrong with asking a satisfied client for help in growing your business. Every client I've used similar language with has appreciated the importance of doing so. No one has refused this request.
Business development can be hard, frustrating work. You shouldn't go it alone. Ask for help so you can receive it.