I am glad the OP asked this question as the same question has been weighing heavily on me. On both my bikes, 2011 Schwinn Voyageur 7 and the '83 Schwinn World Tourist, the brakes seem substandard. I know the '83 has steel rims and when I first got the bike it still had the original pads that had hardened. I have since attempted to tighten the cables and replace the pads and seen much improvement but still I have not been able to skid the rear tire. I even had the LBS look at the bike and brakes. The LBS gave it a clean bill of health. I didn't know about the leaning back technique. I shall practice that tonight.

The Voyageur does much better than the Tourist but still there are times that I feel like more brakes would be beneficial. I have also tried tightening the cables and adjusting these. In fact, I bought the Park Tool book from Amazon just so I could figure out how to adjust the brakes but I'm still not confident the brakes are tight enough.

I need to find a method of determining grade better. I try to use the Google Tracks app on my Android phone but I don't trust what I am seeing and can't tell where in relation to the ride map the grade is the steepest.