I've found that the cheaper processed meats (chicken, burgers etc.) have the most convincing plant-based alternatives, usually from soy protein. Any seafood or dishes where the meat is the main flavour such as steak there's just no alternative that comes anywhere close; same goes for vegan alternatives to cheese. What I found most helpful when going vegetarian was realising that it's not an all-or-nothing type situation, and if I can go completely vegetarian except for eating tuna or steak a couple times a month then that's better than not trying at all, even though that's not an argument I've really seen repeated all that much on the internet.