That's very difficult to predict, though! There is some correlation with short-term success, but not that great correlation; there are plenty of people "famous in their day" forgotten 20 years past their death, and a substantial number of people whose work only seemed important in retrospect, or after it was recontextualized by a later writer who somehow dug up some obscure work and took a liking to it. I have a minor personal hobby of translating encyclopedia entries from the Allgemeine Deutsche Biographie, the main German-language biographical encyclopedia of the years 1875-1912, into the English Wikipedia, and it's amazing how the space that the writer of the time saw fit to devote to a person often correlates badly with a 21st-century assessment of the person's importance.
Of course, that doesn't quite tell you what to do about it. I personally tend to lean towards, do something that seems interesting to me, with the caveat that I also need to eat. I'm not as worried about making a name for myself 500 years from now, although "seems interesting to me" probably includes some part of that evaluation in it (things that seem likely to outlast me probably get a boost in my personal evaluation of interestingness).
Of course, that doesn't quite tell you what to do about it. I personally tend to lean towards, do something that seems interesting to me, with the caveat that I also need to eat. I'm not as worried about making a name for myself 500 years from now, although "seems interesting to me" probably includes some part of that evaluation in it (things that seem likely to outlast me probably get a boost in my personal evaluation of interestingness).