関わる方法を取っていた you can think this way to make it understandable I think. It had been getting clearer the way how I behave towards people. ・あの人は絶対に嘘をつかない。そういう人との関わり方をしているので、いつも信頼される。 this is an example I can come up with. I never really thought about this grammar, but I think 関わり方をする is mostly used when talk about people's behavior. hope you can get more detail and wider idea of this :)