Would indicates something that might occur whether you want it to or not and is usually associated with the conditional. I would go to the zoo but it is raining. I would go to school but I don't enjoy maths. Wish shows hope for something happening. It can be used for example when blowing out candles on a birthday cake - "Make a wish" e.g. make some hope for the future. Wish could also be used similarly to would with a conditional but in this context it shows more of a hope that the event will occur. I wish that I could go to school but today is Saturday. It doesn't have to have a conditional though. I wish that my Czech was better than it is! Hope that makes sense

Thank you very much, really complete and understanding.