I would never say your suggestion, though others might. It’s a little vague and folksy for me. Depending on the context, more mainstream are: That’s not how I do things. That’s not my way of doing things. That’s not my practice. (In speech you can emphasize the ‘my’ to contrast it with another way already mentioned.) That’s not something I would (ever) do.

That's not how I handle things.

You can say, that's not my style.