If those slide pins are allowing free movement, the brakes will self-adjust side to side, therefore wear evenly. If the slide pins don't allow free movement, nothing else you can do will help.
Sometimes they just need lube--any old waterproof grease, liberally applied. Sometimes they're so rusty that you need a judicious bit of filling or sandpapering. Once in Uruguay I tried to ride my bike with the disk lock in place, which bent my caliper so badly I had to detach it completely because I was wearing through pads every hundred miles. That took a proper mechanic to fix, a thousand miles down the road in Brazil.