The funny part is a lot of times you don't have to do anything special for them to think you got lucky. Just keep an even composure and don't act like you're up to no good. If you don't smirk when you leave them tough sometimes people assume it's luck. If you play a dead carom or such they think it's luck. A lot of people want to believe in luck so you really don't have to do anything special, just keep a steady demeanor, aka poker face.
They blame luck and rolls for wins and losses. Sure, sometimes this is true, but they believe it happens 10X more than it does... maybe protecting their own ego or something. It's hard to say.
When someone complains about a "lucky" shot I did in 9B I like to say "That's why I like 9B, it allows you to get creative." That usually gets them talking! Notice I neither confirmed or denied if it was luck or intentional. It may have been luck, but most likely it wasn't.
"I just had a good feeling on that one" "I knew something was going in the side pocket, just wasn't sure which one." "Heck I don't know, I just trusted my subconscious to make it work" "Oh you didn't know the 2 rail was dead?" and so on. I think a good BS detector is a must for pool, especially one that works on ourselves.