Include traditional contact methods, such as phone and fax numbers and a postal address. Invest in security. Respect your customers' concern about credit card fraud by offering various methods of payment. Use a secure server for quick online order processing and a postal address for them to send their order the traditional way. Spam signals deceit.
People are naturally very hostile to and suspicious of unsolicited commercial email.
Spamming is a sure fire way to undermine people's trust. Deliver your messages only to people who have initiated communication with you first, either by using one of your services, or by explicitly asking for more information. Most small businesses rely on word of mouth advertising. Neighbours and friends tend to talk about their buying experiences, offering recommendations if the service was good, and recriminations otherwise. Trust is liquid, flowing through recommendations and referrals from one satisfied customer to the next.