This week is my 8-year Googleversary (anniversary at Google), and my 17th career anniversary. That seems so long. I remember starting at Google, and at my first job, like it was yesterday. But 86% of FTE's company-wide and in my department are newer than me.
I know it's cliche to pass along observations, instead I'm going to pass along things other people have taught me (numbered in no particular order):
1. It's a marathon, not a sprint. Pace yourself accordingly.
2. Do your absolute best on every task, even the small silly ones. If you can't do the easy stuff well, you won't be given harder / more interesting stuff to do.
3. Seek out career coaches / mentors, and use them. And when you get to a point where you can mentor others, be sure and do so.
4. Take advantage of downtime, whether it's evenings, weekends, holidays, vacations. We're a big company with a lot of smart people - no one person should be so critical that major problems arise because they are OOO recharging and disconnected from email.