I've been theorizing on this for many years so I will elaborate a bit but summarize the best I am able. First, what is a utopia to you? If you want it to mean never working, having your every whim provided, and only living for pleasure then you are just a wishful king with no kingdom. Only a ruler can ever achieve such a thing and it can only be provided from the energy of thousands of men for the profit of one. That's not a utopia, that's modern serfdom. Then there are the ones who believe that perhaps (after they are long dead) there will be robots providing all this work and energy for us and many people can live like kings. Or perhaps we will make them too smart and they will be the kings and us the slaves? So then let's define it as sane men. We want freedom, peace, good health, minimum necessary work with more free time, an ample and cheap supply of items we desire, perhaps a longer lifespan with less aging related issues. Of course that's not all, we all want comfort and safety and happiness, etc. A master list is needed. Then, define what takes those things away from you, your family, and your neighbors. By removing those things from our lives we will achieve a realistic utopia. So easy, right? Of course not. Listing and deciding to walk this narrow path could be achieved in a matter of an hour. The difficult part is when conflict arises, who settles that conflict? And do not forget the powers and kingdoms that already exist who will not take kindly to us carving our own path through their empires. Those who choose to work together for these goals must do so inwardly instead of outwardly, and then slowly many other such communities all under the same goals and understandings must also work inwardly as a whole group. Of course all of this is just a drop in the bucket, but it's flowing in the right direction I suppose.