Before buying a jet, set your budget and understand annual operating costs. Then define what you actually need: flight range, how many passengers, and whether you want a newer or older plane. These specs narrow down which aircraft make sense for you.
If anybody's looking to buy their first private jet, the first thing you have to know is what's your budget. That's the most important thing, of course. Not just your acquisition budget, but what are you prepared to spend every year to fly? The next question, of course, is how far do you have to go? How many people you want to carry? How old is an airplane you really want to be able to buy? Those kind of things filter out all the other airplanes that really don't meet your needs, and it makes the selection process much smaller, much more finite, and much more specific to your parameters.