I think something that is often overlooked when one sets out on a predetermined path is that sometimes, "opportunity knocks" in a way we never expected. So for that reason, I say it is important to not be so focused on going where we intended that we don't stop to explore the possibility of a different path.
For example: During my last few days at the police academy, an instructor approached me about an opportunity to go to work for a major insurance company handling insurance fraud investigations. All I could think of was, "why is he trying to get me to leave law enforcement? I just got here!" I never realized what he was trying to do FOR me, as I thought he was working against me!
Fast forward 25 years, I was involved in a lawsuit, and, because that lawyer saw a lot of potential in me as we worked on my case, he asked me to do some part-time work for him. Had I never met him, that would never have presented itself as an opportunity. While I did not go looking for it, it definitely fit with my interests.
So, while most people will talk about research, staying focused, studying, etc., I am here to tell you: keep your eyes and ears open, and be willing to consider other opportunities that come your way! If someone says, "hey, would you be interested in going into xyz business with me?" don't be too quick to say no. Instead, say "that sounds rather interesting. Let me give it some thought. Can we touch base sometime next week?"
The world is full of wonderful surprises!