Earn the experience through different levels of work and when you feel like you have gained all that you can from it, consider moving on in other companies would widen your horizon on different business cultures. Putting more experiences in various positions would make you a more valuable asset for companies and making you a better option for higher rank duties.
Donating plasma can actually work out better than selling your blood. It takes longer to donate plasma because they will put your red blood cells back in your system. The upside is that you can donate plasma as much as twice a week and you can make anywhere from $40-$60 per donation. You can make that $100 in less than a week if you can stomach the needle.