I've cold called (hated it).
Did mailings (pricey).
Hired salespeople (didn't work out)
Left flyers (time consuming)
But when it is all said and done, the easiest way I've found to get clients is to just talk to people. I am not talking about going to friends, or getting referrals, or going to network meetings.
I am talking about going about your regular day and chatting with folks.
Here's what I mean: I went to my local Apple dealer to take care of some business and looked across the parking lot to find a new frozen yogurt place.
I walked in. It was beautiful. It looked like a retro 1960's place with several machines coming out of the wall where you could "self-serve" your own yogurt.
The place was so remarkable, I asked the clerk to talk with the owner. She said he was her brother and that he was at the other store... one town over. I thanked her and went out the door.
Found the other yogurt shop. Asked for the owner, "His sister, Ann, sent me," I mentioned.
The owner came out, we talked for 20 minutes, and the owner said, "We've got to get-together on this!" (He was excited.)
The point here was that I didn't go out that day looking to "Cold call" anyone. I didn't go out to rustle up some business.
I kept my eyes open. I kept my ears tuned in. I kept my mind in gear.
The rest is easy... look for an opening... and take the fruit.