Be a person who doesn't just rest on intimate knowledge of their chosen technology path, but also has a serious grasp of the business logic driving the need for that technology (and by extension, you). In my application (real estate), knowing SQL Server isn't enough, I have to know how agents and brokerages work, the property sales cycle, have a reasonable understanding of the laws and regulations, all the data elements and how they are to be acquired, stored, indexed, triggered, searched, displayed, calculated, and shared... and why. I need to be able to talk to a multiple listing service director as much as I would another DBA.
Be a person who first reads the manual/documentation, googles for answers and information, and can demonstrate at least some degree of effort before going to a coworker or mentor for answers. Be a person who can say "I've gone over this several times, I know I'm staring right at my problem but I'm not 'seeing' it, can you please take a look because I need fresh eyes" when they ask for help. All the senior people above you had to go through that (and may of us still have to on occasion), but don't ask first without a serious effort on your own part, As we used to say, RTFM.
And have fun. Yeah, there will be deadlines, stressful shifts, all-nighters/weekenders, Dilbertian bosses, incomprehensible customer requests, co-workers from hell, and code to debug from a deeper hell, but you're doing what you love to do (I would hope), you're being challenged on a daily basis, you get to be creative, and you're solving real world problems for people and hopefully making it a better place.