How to save $450 a month? We live in teh country which means our house is propane powered? Any tips for saving

I had to move out to be closer to my college, Now I'm back saving every penny I make this summer to spend on housing, food, college. I'm looking for any tips saving electricity. We have three fish tanks, a computor, a veggie garden,I make cleaning supplies out of vinegar stc, looking into making my own laundry detergent and I hang dry our cloths, I go back to school in september. Any ideas to make more money I tried to advertise housecleaning with flyers that didn't work, any better way,energy/propane saving ideas?