To me, a simple way to define success is having a goal and working towards it. If you know why you are waking up in the morning you are successful. You are a failure if you don't have any goals or do not know why you are living. A person with a goal is just as successful as anyone else. Success is being in the process of building the life you want.
Absolutely agree with you. Success as defined from a personal stand point is down to achieving goals (exams, healthy living, getting a mortgage etc).
If you want to look at success from the stand point of others perception of your life (as a success or not) then the rules totally change. We are no longer in charge of the parameters which we may decide makes us successful in life, it is now down to other people projecting their own personal parameters which they feel defines success on to us. While I may feel successful because I achieved happiness other people may look at my crappy car and decide otherwise.
This does bring in the point that you can only make decisions about other people with the information you have. I can only tell I fancy a woman by her looks initially but there could be instances when talking to someone I don't initially fancy may change my mind and now I fancy her.
If you want people to know you are successful without them getting to know you then money and owning nice things is the only way to go. It is a superficial as that. It is not necessarily their fault but rather the lack of information they have to make their decision. Why go to an interview not wearing a suit? you wear one because there isn't enough time for the interviewer to infer that you are a successful individual, you have to help them make that inference from the start.