(This post is part of a bigger list of rules that I have found helpful for thinking about a career, and beyond. See this post for an explainer).
This is possibly the most important rule, and thus I am putting it right at the start. The way this rule is phrased is partly inspired by Y Combinator's rule for startups: make something people want. If I were asked to condense career advice - specifically in academia, but I think also more broadly - into four words, it would be these: do novel, interesting things.
The rule is really composed of three sub rules: First, do something (surprisingly underestimated in my experience). Second, do something that is novel. And third, do something that is not just novel, but also interesting. Let's take a look at these, one by one.
Do something
I find it hard to overstate how important this is. I've met countless of brilliant young people who were clearly very smart and creative but had nothing to show for it. In academia, this is often phrased in the more negative "publish or perish", which I think is slightly misleading and outdated. What it should really say is "show your work that demonstrates your thinking, creativity, brilliance, determination, etc.". It doesn't have to be papers - it could really be anything. A blog. A book. Essays. Software. Hardware. Events you organized. Whatever - as long as it has your stamp over it, as long as you can say "I did this", you'll be fine.
I need to repeat that it's hard to overstate how important that is. As Woody Allen famously said, "Eighty percent of life is showing up". This is why I urge anyone who wants a job in a creative field - and I consider science and engineering to be creative fields - to actually be creative and make things, and make them visible. The most toxic idea in a young person's mind is that they have nothing interesting to say, and so they shouldn't say it in the first place. It gets translated into not showing what you've done, or worse, into not even doing it. Don't fall into that trap (I've written a bit more about this in a post entitled The curse of self-contempt).
Do something novel
Novelty is highly underrated. This is a bit of a personal taste, but I prefer something that is novel but still has rough edges, over something that is a perfect copy of something existing. I suppose the reason most people shy away from novelty, especially early in their career, is that it takes guts: it's easy for others to ridicule novel things (in fact, most novel things initially seem a little silly). But especially early in your career is when novelty matters the most, because that's when you are actually the most capable to be doing novel things since your brain is not yet completely filled up with millions of other people's ideas.
Novelty shouldn't be misunderstood as "groundbreakingly novel from every possible angle". It is often sufficient to take something existing and reinvent only a small part of it, which in turn may make the entire thing much more interesting.
Do something that is also interesting
While novelty is per se often interesting, it's not a guarantee. So make sure that what you do is interesting to you, and at least a few other people. It's obvious that doing things that are interesting will be good for your career. This doesn't need a lot of explanation, but it's important to realize that what is interesting is for you to figure out. Most people don't think a lot about this, and go on doing what everybody else is doing, because that must mean it's interesting (when in reality it often isn't, at least not to you). The ability to articulate for yourself why something is interesting is extremely important. Practice it by pitching your ideas to an imaginary audience - you'll very quickly feel whether an idea excites you, or whether you feel like you're just reciting someone else's thinking.