I did a CPL on a distance learning package. I then did a FIC course and instructed part time. Then I did my Multi-engine instructor rating.
In the first year I added some 300 hours in between another full-time job. The ME instructor rating helped me to build multi-engine hours free. I did my IR in less than 10 hours in the days when you could.
I then flew traffic-reporting aircraft for 6 months, and this allowed me to reach 800 hours including 150 multi-engine.
Then I got part-time work flying for a small airline and an air taxi company. I have been doing this for 5 years and I am 41. I now have 1700 hrs+ including 700 multi-engine. But I am not making a career out of it.
I must say that two things helped me in this:
Right place, right time
Knowing people who know what's coming up.
Good luck!