If you do a search, there are quite a few threads with pics of meals etc to help give ideas.
They generally love meats, feeders and fruits - I love to feed treats occasionally, but generally I stick with healthy meals rather than meals they will love, so greens / veggies mixed in there.
Lots of breeders use a very simple diet of dog food and frozen veggies or greens with supplements. So it doesn't have to be difficult or fancy. I usually feed a bit more variety than that, because I have the time to prepare meals. Most often I use canned dog food for protein, they also get bits of cooked chicken, beef, turkey, raw or cooked eggs, dew worms etc if I have it and want to throw it in. For greens / veggies - I feed whatever I have in the fridge, with more emphasis on the healthier ones. So if I have squash, arugula, mushrooms, bell peppers and spinach then I might feed some of all of them, but put more of the first three in and just a bit of the others for variety. If I don't have much time then I'll just feed some arugula and dog food. I also had a ton of healthy stuff at one time, so I put it all in the food processor and froze it in ice cube trays - so often I will use some of that instead of bothering to chop up fresh stuff. The frozen stuff has dandelion, arugula, watercress, spinach, butternut and acorn squash, green beans, mushrooms, carrot, broccoli and maybe some other stuff in there.
I'm attaching some pics, some of them are pretty old.