It seems having a backup career, or a career to help build capital to fund training is very important...
Sherlock,
If you have no funds to pay for you fATPL, then I would hardly call your ONLY career a back up?
If you want some advice, some concrete advice, then tell us a little bit more about yourself. I can't really see where this question is going. If you get replies back saying "accountants", "doctors" etc, then would you really go to UNI to get a degree so you get a well paid professional career to then fund your flight training?
On the other hand, during ATPLs, I've read that security work is the best option. 12 hours a day of reading your books - probably more than full time ATPLs do.