With dreams taking longer than ever to achieve, the ride can seem long and dark at times. Having an all or none approach can add to this. This is where you have one big end goal, which probably won't be achieved until 10 or 20 years later. Meanwhile, you will have a decade or two of feeling not achieved, desperately asking 'are we there yet'. This could be enough to zap your spirit out before you can get to the end.
Therefore, there are two things I wouldn't recommend a person to set out on their journey of dreams without: a roadmap, and a sense of priorities.
The first thing is to get your priorities right. You want that package that is your ultimate goal at the end, but you have to decide which parts of it you really want the most, and which parts of it must come before the others. Set out on achieving these first.
Say your goal is to live in New York City and write a book about it. However, you currently live in a small town in New Zealand, and don't even have the money to travel to New York to have a look at the place. Your two first goals may be to familiarise yourself with New York, its landmarks, its culture and the way people think about it, and get a higher paying job so you can save some money for your eventual move. With the internet nowadays, it is very easy to get somewhat familiar with big global destinations like New York. You can get familiar with where things are in the city for a start. Google maps or any other mapping application can be useful for that. You may try to get into Street View and 'walk' a block or two to get a sense of how the places connect together on the street level. You would also try to read the many articles people write about New York. Articles like 50 Things I Love About New York or 40 Reasons to Hate New York, or even things like 30 Signs You Grew Up in Manhattan can be very useful sources of information for you. It will take years to go through all of that and get it absorbed into your brain, trust me. Meanwhile, during your day, you may like to start looking for a job if you don't already have one, or look for a second job or a higher paying one. You may decide to return to education so that you can get even higher paying jobs later on.
Then you need to draw up a roadmap. Using the example above, once you have saved some money, your next step may be to move to Auckland, the largest city in New Zealand, to get a feel of how city life is like. Auckland may be a lot smaller than New York, but it has skyscrapers, international food and lots of business activity, some of the experiences you will find in New York. It may help you get used to New York when you eventually get there. An alternative would be to take a two month holiday in a nearby large multicultural city like Sydney, Australia, which also has all these things, perhaps on a slightly larger scale. Meanwhile, you will want to continue to connect with the cultural phenomenon that is New York. You may want to watch so many New York movies that you become so familiar with the settings you can point to where they are exactly on a map. You may want to make some New York friends online. When you feel you have enough knowledge and connection to New York, perhaps you can start writing parts of your book. You will have to modify and rewrite parts of it when you actually get to see the place, but it's great to make a start when you already have something to write.
Eventually, your dream may be achieved in a similar fashion to your roadmap plan, or maybe not. Maybe you'll find something even more suitable in your life. But in any case, none of it goes to waste, and every bit of it would have helped coloured your life vividly. Twenty years down the line, it's quite likely you would have lived in New York and finished your book. Or alternatively, you may have decided to just settle in Auckland, but have a cultural connection to New York. By then you might have already seen the city on two or three different trips there during your annual leaves, paid for with the money you saved over the years. Although you didn't write a book about living in New York, you did write a book about your connection to New York and your opinions about the city as a New Zealander, an even more unique thing. You might have also written another book about living in Auckland, or perhaps a book comparing and contrasting the two cities. Either way, the dream did not go to waste.
One important thing is that you enjoy the process as much as the outcome. In my example above, there would be new experiences and inspirations every year along the way. It's not the final act of moving to New York (or not) that mattered, it's the knowledge, experiences and friendships gained over the years that were the main gains from this big dream.