It will make the bond stronger, and they will give you important insight (and if you sell to them immediately after, you’ll get higher conversion rates.)
The primary technique is to ask for their advice on something. Asking for their advice (and not opinion or information) makes them cross over to your side. They are now your trusted advisor because they have committed to helping you. This can be done in a retail environment, website, email, etc. If they react you will gain insight from them, and you might want to make them a special offer after they reacted – they will be more open to it so your conversions should be higher.
You have enough fixed POS stations in your store for regular business, but sometimes you have special events and the lines become too long, customers are unhappy, and you are losing money because some just walk out or are in a grumpy mood when you offer them some upsells.
Use handheld POS terminals that work wirelessly, and have extra help go to people standing in lines to pay and process the payment for them where they stand quickly.
If what you are selling has a long run effect on your customer (exercising, financial security, passive income, etc.), it can help if you connect them to their future selves.
In your communication, show them or send them their picture (you can ask it from them for a surprise you’ll be sending them) age processed, software can create their image an X number of years from now. Of course, your message should be congruent with this idea, and help them realize that their future self is the same person they are now, and why it is important that they invest in their future (by paying you.)
You might have occasions when you had too many customers wanting your service at the same time. Maybe you advertised an exclusive deal for the new gadget you now have in store, or maybe too many people want to get their mobile device serviced, etc. you have a long line of potential customers, and you don’t want to lose them or make them angry by having them wait in line.
Tell them approximately how long it will take, ask for their mobile number, and tell them you will call them or send a text message when they are next in line (give them five minutes to get there). They now have time to get some coffee, go shopping, etc. if you want to be even nicer, offer them a free coffee or cake coupon for a nearby place. This way the waiting time will not only pass faster, but they’ll have a much better experience, and it’s all connected to you. You have turned a potentially bad experience to both of your advantages.
Relieve congestion of customer service calls.
Tell them that if what they need is not urgent, to call back at a particular time (or even better, offer to call them at that time) for immediate service (or a shorter wait.)