down to a fine art

get/have sth down to a fine art
get/have sth down to a science
(learn how to do sth perfectly; to be able to do something very well, usually because you have been doing it for a long time) —
довести до совершенства; натаскаться;
~ наблатыкаться, насобачиться (груб. разг.);
филигранно овладеть чем-л.; преуспеть; делать что-л. по всем правилам искусства

Example:
Now what can I do for you today, Miss Randall? Need some special supplies? I know things aren't too fancy here, but I can order just about anything. I've got it down to a science by now. Anything you want, I can order.
(Susan Krinard, "Prince of Wolves")

have something down pat (to learn something so well that you do not have to think about how to do or say it)

Example 1: Jim always used to miss his train, but now he's got it down to a fine art and knows exactly what time to leave the house. — Джим всегда опаздывал на электричку, но сейчас он довел это до совершенства и точно знает, когда выходить из дома.

Example 2: She's got shopping/sandwich making/etc. down to a fine art. — ~ Походы в магазин/Приготовление бутербродов она возвела в ранг (высокого) искусства / довела до совершенства.

Example 3: Bud had his answers down pat, but he knew there could be some questions on the test that he hadn't thought of.

hone to perfection

Example: The BEST sangria recipe I've been able to hone to perfection! — Лучший рецепт sangria, который мне удалось довести до совершенства!