Know your role. Seriously know your role.
Why do you have a never ending pile of shit to do? It's your own damn fault. You've let on that you might know something. One time you might have even volunteered for something. That was a huge mistake. Do you really think your company is going to hire someone to do the role you used to be doing? Nope. Now you've got two jobs (at least) and you work in tech, which means you're an overtime exempt employee. No overtime for you. Buy some Adderall off the interns, you're going to need it.
Play dumb and succeed.
If you really want to kill it, you master your role and act like you don't know anything else. No one will expect anything from you other than what you were hired to do. You won't suddenly be stuck carrying the entire company on your back. This is as true for beer league softball as it is for your career. Winners play dumb, they also get weekends.
Know how to value your time.
If you're hired for $60,000 a year and you get two weeks vacation (or maybe you're lucky and you have unlimited ~vacation~). That means you make $30 an hour pre tax. If you're working 10 hours a day, suddenly you're making $24 an hour, equivalent to $48,000 a year. Congratulations! Your ambition just gave you a $12,000 pay cut.