if looking for a part at junkyard how can you find out what parts off another year or model will work on the car you looking for
Look up part numbers for the different years on the internet and see if they match.
It sounds simple, but this really is the best way.
Unless you are in a big city like LA, there are really no good (legal) chop shops (that I know of) that you can just go and request a specific junk part. I personally use pick-and-pull here in norcal. You can find year and model of car (typically years are like 2018-2020 or 1990-1999, they encompass a certain version of said car...) and then go and check it out with no guarantee that the part will be there by the time you get there. Of course this way you would have to tear it up yourself. Or you could just ebay I guess if you don't want to get your hands dirty? All you have to do is just Google your make and model and it would have comparable results say to when before there was a refresh. A good example is how camrys look like now compared to just a couple years ago.
If you are looking to say put ford shocks and suspension on your bmw... If that's your question, That will require research and possibly fabrication. If your question be can you put honda accord wheels on a honda civic, or honda accord fuel pump on honda civic, more than likely it should be okay? Just Google and you will probably find your answer to be more then sufficient compared to my response haha
Some of them will provide you a list of vehicles on their lot that have the part you are looking for, doing the cross referencing for you. LKQ does, don't know if you have one locally. Also check car-part.com
Also a good idea to look up compatible vehicles that share the part you're looking for online before you go to the yard (not too hard to do). Recently went to Pick-n-pull and the list they gave me had some newer year models which I knew were not compatible with the EGR valve I needed.