Across a decade, I have been working client-side with several digital marketing agencies (both global and local ones) and I am also collaborating with a very young digital agency as a consultant.
In my opinion, for young agencies the best customer acquisition strategy pass via referrals. Delivering the best service to your current customers will dramatically increase the chances of getting newer clients via them. From my experience, specially in some sectors (Retail, Consumer Goods, even B2B) this is one of the most effective strategies.
On top of that, you would need to have your digital marketing and communication strategy sorted out. For instance:
- have a relevant, clear, SEO optimized website
- a coherent social media strategy across a variety of channels. Social Media is key to reach a broad variety of leads
- a localized PPC strategy may also work under certan conditions
- depending on budget, some digital agencies also run "guerrilla marketing campaigns".
Happy to provide more details in case you are interested.