It is not enough to service your clients, or even to service them well.
Whenever possible, go above and beyond. Make suggestions, deliver something extra, spend time, empathise, care. Put the proverbial bow on the box or the cherry on top of the sundae.
Someone might be offended, but it is worth the risk.
You may end up with a fan who will gladly, and voluntarily, sing your praises.
A couple of those and you have yourself a career.