Just think about this. If you recently developed a love for the iron man suit, how much more the thousandss of die hard Ironman fans all over the world and tech gaints would thought about the same thing..? Yup, there are more than enough people who would like to have a suit similar to that.
Let's have a look into the suit in the movie. If you have gone through the previous editions of avengers you would see many things the suit can do. In the series "Ironman" (a trilogy), the origin and development of the suit is shown. Tony Stark (portrayed by Robert Downey Jr) makes the initial suit - Mark I, for the purpose of escaping terrorists who held him under captive. From then on, he works on the suit and develoos it into the current latest version, Mark 50.
The suit, as shown in the movies, is powered by an arc reactor. The arc reactor is able to generate more than adequate power to make an average human heart work for 15 years per second. Well, in short so much amount of power. Additionally it can absorb the external power from activities like explotion and similar events.
So, the major thing in the development of the suit is the Arc Reactor. And then there is Jarvis (a.k.a FRIDAY), which is Tony Stark's personal assistant. It is another technology highlighted in the series which is actually an artificial intelligence system which acts as his personal assistant.
Now, let's come to the practical side. The Arc Reactor is, well almost impossible go develop (I won't say completely impossible, because technology is fast growing). But as of now, many tech gaints has worked on the same, and still nothing seems to happen. So, I assume, as of now, the arc reactor is just "Stark Things" which won't happen in reality. But, there are alternatives. If one is able to come up with another kind of energy source, which can power up the suit (which is another big hurdle), the concept is possible. But, the energy source must be sufficient enough to do works like lifting the suit up to sky, powering the computing processors needed, etc.
So, now let's assume you get some sort of energy source needed for it. Now it is the time for suit development. Ironman suit is kind of Armor for him and thus have a lot of option to fight - guns and fire power. You can choose what you need in your suit and after you choose you need to have adequate knowledge or get someone with adequate knowledge to install it all into one single piece of art. Well, that will give you the suit.
Now, we have another character Jarvis - Tony Stark's personal assistant. Jarvis is another kind of Siri, Google Assistant, Bixby and all but more personalized and intelligent. This one is more practical in the current world scenario. There was news that Facebook CEO Mark Zuckerberg is working for something similar to Jarvis. In the movie, Tony Stark get the help he needs from his assistant, rather than employing someone else. It is reliable and trustworthy to him. So, if you could develop something similar, it will get your work on an easy course. You can get adequate information and valuable feedback for developing the ready to factors. So, I suggest to develop this one first.
Hope that this can get you some insight. Would really love to see if anyone could actually make it work.
~ a fanboy of "The Invincible Ironman" and "Tony Stark"