I think that it depends on what you mean by Grow. I'll go ahead and make some assumptions based on your bullet points; you mean grow revenue, you have existing customers, you produce good work.
Word of mouth.
I highly recommend using the Net Promoter Score®. Conduct a simple follow up with every customer after the project is closed out, asking them on a scale of 1-10, how likely are they to recomend their experience to their peers. If they answer an 8 or higher, they are considered a "promoter" if they answer a 6 or lower they are considered a "detractor."
Follow up with both types immediately.
Follow up with your detractors right away and see how their experience could have been improved. What could you have done better next time to elevate them to an 8 or higher.
Your promoters are your bread and butter. Follow up with them and _ask_ them to spread the word about your company. Give them something that they can share with their friends that makes them look good, providing them with a unique discount code that they can share with their industry peers. The discount code entitles the referrer to a kickback and the new customer to a discount. We call this a _dual-incentive_ structure. It allows your promoters to spread the word about your services without coming off as spammy or exploitive.
A recent Texas Tech marketing study discovered that 83% of respondents would be willing to refer new business to a brand they love, but only 29% of them actually do.
If you'd like to discuss the specific details of your organization in a more private forum lets schedule a call and chat.