In addition to all the good things already mentioned:
Don't worry if you don't know everything, the most important part is to know where/how to find it (know your resources, books, fellow-coders, networks ...)
Don't worry about challenges, if it were easy we wouldn't need trained coders.
Be open-minded! If you ask 50 coders the same question you might get 50 answers. Some things are more subjective than others. Just because there are different opinions, doesn't necessarily mean you are wrong, so trust your skills but at the same time listen to your peers and judge what makes more sense. (Well, I hope this makes sense to you.... )
Finally, enjoy what you do whenever you can. It's more fun that way.
Best of luck!