Make them second nature. You are there to write. It means avoiding too much scene setting and description and getting to the good stuff—the guts of the story. However, don't automatically give them charge of your brain, or anything else — they might be bitter, twisted, burned-out, manipulative, or just not very like you.
I know those answers sound flippant, but my point is, speed is not the point. Game of Thrones is a great example of this.
If something is proving too difficult, give up and do something else. Change the tense. Do you like architecture, museums or historical places? Stop arguing with yourself.