I've got two Runner Ducks who were about 3-4 weeks old when we got them. They are slowly but surely getting more friendly towards me. But its not a deep friendship like with a cat or dog, its more like a formal friendship lol. I don't know that ducks will ever be bosum buddies like cats or dogs unless they are hand raised from the egg and you are the first being they see... and you take great care with them so they continue to think of you as the momma duck. Even then I think its a rare thing to have a happy lap duck (though it happens).
To make friends with my ducks I am very carefull to walk and talk softly around them. I keep a relaxed energy around them and try not to do anything that would make them think I'm stalking them like a predator. When I must corral them I do it gently and talk to them softly while I do it. The same talk I talk while cleaning their pen and food water.
I try to never make them do anything they don't want to. I used to pick them up twice a day to transport them to and from their day pen. Over time they stopped fighting it (and I carried both together to avoid seperation anxiety). But although they grew calm they really didnt like it I'm sure. Now I tilt a Rubbermade Tote on its side and with a gentle nudge they walk right in. They actually seem to like the ride. And as I carry them in the tote, sometimes one of them will place its bill ontop on my hand.. just like they do to each other. They show other signs of affection, like coming to the end of the pen I am sitting at. And they geniunely seem to like seeing me every morning. In the brooding days everytime I came near their pen they would sit down. Now they often walk close and hang out near me. And sometimes they mimick my talking. But they still will go to a corner and sit down sometimes. They need time, patience and respect.
They still are not sure about this new life yet. Its unnatural for them. They need time. I've taken a few oppurtunities to pet their heads and bodies. But only when they seem calm and don't flinch or seem to want to run away. If they run from you don't chase them. Don't pressure them. If you must herd them then do it consistently and do it as calm as you can. Then reassure them with soft talk when its done. Observe them and learn how they are, then respect their nature and modify your behaivor around them to suit. I'm sure they will come around eventually. Though duck friendships may be unique and we just have to accept that they may not be all cuddly like some other pets. Just take them for who they are and roll with it.