Word of mouth will always be your greatest marketing tool. The more events you manage, and manage successfully, the more new clients you will line up. Happy customers tell people why they are happy.
Ideally 30-50% of your clients should repeat, but with some events that is not always possible. But growing your business just on new customers is costly and most likely not sustainable. So you want to make sure you are focusing some of your marketing resources on getting existing clients to repeat.
But you need to be promoting your event management business if you want to cultivate new clients. In the second half of the second decade of the 21st century, the best marketing model is an integrated model. Your promotion efforts must be diversified and targeted. General marketing does not work, while targeted marketing utilizing content offers has a much higher success rate.
Your promotion mix would include direct mail, eMarketing, blog posts, inbound marketing, telemarketing, and much more. Most important is to have a schedule designating the method, the market, and the timeline. Very often an integrated marketing plan includes multiple campaigns to generate leads and then drip campaigns to nurture leads.
You need to be budgeting monies for marketing, normally 5-10% of your budget, and you must stay on track with your plan.