If you're looking to find a job at a record label then the best route through the door is to get in there for work experience. You probably won't be paid for your work experience, if you prove yourself to be a decent enough worker however then the chances are that they'll wish to keep you on and you'll obtain a full/part-time record label job as a result of it. Send e-mails out to numerous different record labels, get your name out there, create a professional but friendly sounding e-mail template and adapt it for each individual record label that the e-mail is sent to. Ask if there's any possibility of work experience, provide details of your previous work (if applicable), and just really sell yourself as to why you'd make the perfect work-experience staff member.
It's not always easy finding work experience at a record label; if you're persistent enough and continue to send e-mails to numerous different labels however then the chances are that eventually you'll make the breakthrough and achieve a placement of some description. Even if after the work experience the record label doesn't decide to keep you on; that experience will no doubt prove to be invaluable for further working opportunities and you'll then be able to apply to further record labels and state that you do have experience in the field of record label work.
Once you've got your foot in the door it will then be a lot easier to find further record label work in the future. Record labels almost always look for previous experience when hiring in new positions; if you've had record label work experience this therefore puts you in a fantastic position to gain further jobs as record labels will see this experience and take note of it. Persistence pays when it comes to record label work, as long as you're tenacious and determined; you will eventually make the breakthrough and obtain record label work of some description. You won't start at the top, you'll have to gradually climb the ladder and eventually a few years down the line you could find yourself to be in a serious position of record label power.
If you seriously want to work at a record label then set your mind to it and make it your mission to achieve this employment. If you're focused and driven, persistently sending out e-mails and phoning up record labels whenever possible; your break will come and your continued display of determination will most definitely pay off. It's not always easy to find work at a record label, if you keep at it however and continue to try then your passion will pay and a position of record label employment will be achieved.