I kind of fall into the same category as Jan and Sue. I'm not strictly a vegetarian either, but I eat very little meat and virtually no red meat at all. For practicality, I will eat chicken or turkey if I am out somewhere and there are no other suitable options (if I'm not at home, it can get tricky at times to go meatless, as I have other dietary restrictions which I'll go over in a little more detail below).
I do consume fish, eggs, and dairy. And if you do eat dairy, cottage cheese and Greek yogurt are both fantastic sources of protein. But if you are looking for good non-animal sources of protein, then tofu, quinoa, peanut butter (which I do eat a lot of), other nut butters, and lentils are all great. Hummus (chickpea) is also a really good source of protein, and it's tasty to boot.
Chickpea butter, sunflower butter, and soy butter are other options and are now widely available in most grocery stores, as many schools have gone peanut-free and parents are always looking for suitable alternatives to peanut butter. There's a soy butter brand called Wow Butter which is pretty good.
With all of the above in mind, I have the added problem of adhesions which have caused a number of partial obstructions, so I have had to modify my diet accordingly. That basically means that most raw vegetables, nuts in excess, corn, or cooked vegetables with tough skins or casings are all out. Despite this, I have still be able to stick to a modified diet and eat very little meat at the same time. So even if you do have some dietary restrictions, it is possible to stick to a vegetarian/vegan diet if you know your options.
There is certainly a wealth of information online regarding vegetarian and vegan recipes, or if you choose, a dietician can be helpful if you are basically starting from scratch.