If I were ever asked, this is what I would tell young researchers embarking on their career. They are in no particular order. In fact, 8) may be the most important.
1) Understand your problem as deeply as possible. You should know everything that there is to know about your topic. Always ask the next question and think hard about how feasible it is to answer it. Know why it would be hard or easy to do so.
2) Learn as many tools as possible. Get into the habit of constantly learning about new methods. You may not need to implement everything yourself but be aware of what is out there and even more importantly who knows how to use it.
3) Be known as an expert in something. You don’t necessarily want to be pigeonholed but it will always serve you well if you are known as the expert in a certain area.
4) Knowing what you don’t know is as important as knowing what you do know. This goes with having deep knowledge about your subject. You should know whether or not the reason you don’t know something is because no one knows or just you don’t know.
5) Do not slack on scholarship; always do a thorough search of what has been done before. Never be lazy about checking references. It is your job to know everything that has been done before. Also, just because it is not on the web doesn’t mean it doesn’t exist.
6) Talk to as many people about your ideas as you can. Getting feedback is extremely important to sharpen your ideas.
7) Never let the lack of effort be an excuse for not getting something done. Sometimes, research is tedious. Sometimes one more calculation or simulation will make a huge difference in your result.
8) Learn to finish. On the flip side of 7) you also have to know when a project is done. There will always be unanswered questions and loose ends. Be aware of which are critical to your result and which would represent future projects. The inability to finish papers is probably the biggest problem young people have.