Things to avoid:

• Stuff that contains pathogens that might multiply - so please don’t add your cat and dog poo, and if your tomato plants get infected by blight, dry them, then burn them, rather than compost.
• Stuff that is likely to attract rodents before it rots down. If you have just a normal compost bin, that means no more than a small amount of fat / dairy. [So, that paper towel you used to wipe up the olive oil spill - on it goes… that carton of milk that went rancid, no thanks.)

Other than that:

• Pretty much everything will compost eventually. All the so-called “rules” apart from the two above are about making things faster. On that basis, you can ignore everything below here if you just want to get started :-)
• Keep a minimum of two bins - one that you’re adding to, and one that you’re not, because you are aiming to start harvesting it soon.
• Some things will rot quickly anyway - a mix of grass and shredded paper / cardboard, and kitchen scraps will be lovely.
• Some things will rot slowly - wood branches, bamboo roots, and the like. You can speed up things a little by shredding them first, or just keep a separate bin for the “really slow” stuff, and accept it’ll take a few years.
• Worms help, as do lots of much smaller things. If you have the opportunity to put bins on the soil, those little helpers will find their way in much more quickly than if you are dumping the bins on concrete.
• It’s easier to put out compost from the kitchen if they bin is near the back door than if you have to tromp down a path and round a corner. Putting out involves lots of journeys with not much stuff, using compost involves a small number of journeys with a barrow-load of stuff. Optimise accordingly.

I could write more complex stuff about bin insulation, and ideal temperatures… but I don’t want to write so much it’ll make the subject look so complex it’ll put you off starting.