Referrals come from many sources. They can come from other businesses, referral services, or from current customers. Companies in a particular field may refer clients to one another. For example, an auto mechanic that specializes in transmissions may refer customers to another mechanic who mainly deals with electrical problems. It is very uncommon for competing businesses to do this, but companies that offer different products in the same field do it quite often. Some businesses exist solely to provide other companies with lists of prospective clients. These businesses are called list services, and they can be a great help in customer lead generation. These services compile lists for other businesses to be used for direct mailing, telemarketing, or business-to-business sales. On a more personal level, satisfied customers may tell their friends and family to buy from a particular business. Good word of mouth can be the best sales lead generator.

Telemarketing is another widespread sales lead generation technique. This often involves someone cold calling people to tell them about their products. Telemarketing has a high rate of failure, as many people do not like receiving unsolicited phone calls. If some people do respond positively, then the telemarketing is a success. Telemarketers benefit greatly if they have a list of referrals to call. This way they are not making purely cold calls, greatly increasing their chances of success.

Advertising is another way to generate leads. Any type of advertising, be it radio, print, or billboard is great for letting potential customers know what products a business offers. Advertising itself has become a huge business. Some of the most successful companies in the world are advertising firms.

Customer lead generation is one of the most important parts of sales. Salespeople are much more successful if they have an idea of who may be interested in buying their product.