Very difficult question is depending what your client looking for:
First, you should meet with Client Face to Face and show and explain what you're doing and what service you provide, and give them several examples, you should have good referrals from your current clients.
Second, if Client looking for some product you should be ready to give to the client for testing, and be ready if a client would like to return that product to you too or bring a product to meeting and give that to the client to see how is everything works for them.
I'll give you my example, I have some client they provide support and services for some communities and the call me and ask for IT help, I came and I spend 4 free hours just to help them to come on track after some local IT big firm, and it was 4 months ago, and yesterday they call me and I have new contact and additional 3 referral to potential clients.

You know we live in a circle world, and our life is big circle too, and if you help someone, someone will help you too because is the same circle