You live the best you can and do what works for you. Generally, I eat organic. I eat a lot of soy. A lot of people complain soy is bad for you. Organic soy is not genetically altered, I've eaten it for many years and I am happy and healthy :) Conversely, when I eat some grains touted as "healthy" and great for you, I end up on the floor with gut pain.
Every body is different and you should learn to pay attention to the cues your body gives you to determine what is good for you or not. A good way to start is a food journal, keep track of what you eat and how you feel physically, mentally and emotionally about 30 minutes later. If you are eating something that doesn't agree with your body - you will notice. You might have heavy fatigue, get grumpy, or feel otherwise "off" . Your body gives a lot of subtle clues what it likes and what it can't tolerate.
For me, I eat mostly organic veggies and produce in season or frozen, for the highest nutrients. I also grow organic produce in the summer to save money.
We eat a lot of quinoa and I do take a B12 supplement daily. If you are a vegan especially, it is imperative that you supplement with B12 - otherwise, just do the best you can like anyone else ;) If you aren't eating processed garbage and you actually eat vegetables I'd say you're doing something right lol - I have known a few "vegetarians" who never ate veggies - not healthy at all!