I have found that be as professional and pay attention to your customers! Offer deals and advertise! Get to know local suppliers and local businesses as they are more likely to recomend or at least know your out there!
Get your business on the front page of google.
I agree with both of the previous answers. Focus on relationships, get to know the guys at the pro-desk at your local bigbox store, if you’re a painter drink your morning coffee at Sherwin Williams. I have had mixed results with lead companies but, in the beginning you may need to try a few. The biggest asset is you, and your work. Be personable, fair in your pricing, do a good job, and ask for referrals and recommendations.
Word of mouth, maybe starting a referral program with incentives.