What is your business's biggest lead source? My experience has been search engines (SEO & PPC). What is yours? Any specific lead generation sources that others could use? Bonus points for B2B lead sources.
With us most of our leads come from industry "influencers". Our affiliate program is in place where they can generate revenue for their referrals.
We've tried advertising, outbound, social, blogs but affiliates are our number 1 source. Our customers love telling their friends about us as well. Even though it's not monetized I'd say word of mouth is our number 2