Gardenfish gave a great answer. I will add that I'm not afraid to toss uneaten cat food and the occasional chicken skin into the mix.
You don't want to add the citrus fruit products because the acids harm the worms. I didn't know about onions. Must be the sulfur. I'm glad to learn something new every day.
I hesitate to agree with adding 10-10-10 fertilizer (though I do note "sparingly"). Any fertilizer that adds up to more than 10 is synthetic and the microbes do better with natural nutrients. Better to just add a shovelful of fertile garden or woodland soils and mix it in. Gentler and already full of the "wee beasties", LOL!
I tend to mow my yard leaves into the lawn each fall, so I don't have them to add to the compost bin. But my County offers clean free nearly-composted mulch and I add that to the compost. I have a double-bin compost system, so mixing it into the yard and kitchen waste is easy.
Is that about the best compost bin or what? The front slats lift up through a slot, the weights of the back make the top easy to lift, and the screens keep pests out and allow air in. Sometimes there is even steam coming off it in Winter.
But composting doesn't need to be tricky. I read once about a lady who just tossed all her food scraps out the kitchen window, and always ended up with great compost. Pile planty waste up and it will break down. Just a matter of time.
