Food is always a powerful motivator. I feed mine peas (thawed frozen peas), and they follow me anywhere for them. Picking them up is another story! I have one that hates being picked up, two that don't mind, and one that will jump up and down flapping her little stubby wings if I'm holding someone else instead of her. I think it's a personality thing for each duck. My poor Swedish FREAKS OUT when you pick her up. Screams and cries and tries to get away. My Cayuga will snuggle down into the crook of my arm making happy peeping noises the whole time she's in my lap.
Long story short: Peas.
Thank you! Someone else recommended peas and I tried it yesterday. I brought them inside and put them in my bathtub to contain the mess. (And, wow, did they get those peas everywhere!) They were so cute and fun to watch though. They certainly liked my hand while I was giving them the peas that's for sure! They came running to it after they figured out that's where the peas were coming from lol. Hopefully if I just keep at it they'll eventually learn I'm the pea giver and like me.