Great, it is a lot easier to build trust and position yourself as an expert if your customers find you through the way you are ultimately selling. ie use PPC ads to sell PPC services, SEO to sell SEO services, social media to sell social media services etc.
If you don't have the money to do that as well just focus on email and Linkedin. With outreach the key becomes correctly pre-qualifying prospects to target, else you waste up to 80% of your time talking to people who are never going to buy.
Whatever services you are selling and however you attract top of funnel traffic, turning them into high-quality leads and being able to close them is a separate problem I have found agencies have.
To solve that remember nobody cares about buying your services, they care about how you can fix a problem they have. When you are nurturing leads, focus on solving heir problems, not selling your services.
To do that I use a combination of the PAS (Problem, Agitate, Solution) framework and an ABM (Account Based Marketing) funnel. That is the most effective combination for getting agency conversions.
