As this is a personal opinion, only you can write an essay about what you actually believe. However, we can still help you develop your ideas.
First, you need to think of what being successful means to you. For some people, success means stability. Therefore, if you have a stable job and a stable home, this would be considered quite successful. For others, success is linked with material possessions. For these people, you are successful when you own a lot. Especially if we are talking about expensive objects. For others, being successful is doing the things that make you happy.
You then need to provide strong reasons and carefully chosen evidence. For example, let us assume that you decide that success is stability. When you provide reasons, you can mention things such as the fact that people with stability have less worries in life, and that such people generally have good long-term habits, which allows them to plan for the future. In terms of carefully chosen evidence, you could look at studies of satisfaction between people with stable jobs and those who do not have them, or between people with no debt and those who have debts.