Most kids are good eaters, you just need to be persistent and not let a little bit of whining stop you from feeding whatever they are eating for that meal. As they get used to their whining having the desired effect, they will do it more.
Same thing with crying and picking them up. Pick them up sometimes, sure. But sometimes they need to be left on the ground and glared at, they can't get the idea that crying = get what I want. Pick them up if they are hurt or need to go somewhere or YOU want to cuddle with them, not because they cried out.
My sister in laws kids are so fucking spoiled now, you can't feed them without an ipad playing videos, or put the little one down for more than 5 minutes. They carry them too much and have entertained them too much, the kids are reliant on it now and it would be difficult to break them of it. While her kids are screaming and need 3 people to manage them, my kid is sitting alone in the feeding chair and eats fine.