There is an old teaching that my teacher has taught me years ago. (I even had a t-shirt made!!) I find it very applicable even to daily life, and I have been trying to teach my children the same. 「正速強威」
First, one must learn to do things correctly - 正 Then one can do things quickly - 速 Eventually, one can achieve the same task with power/strength - 強 Finally attaining a level of authoritative mastery - 威
This process can only be achieved through practice. There simply isn't a shortcut.
The following teaching was passed on directly to me by Yamato Ryumon sensei (大和龍門 師匠)
(Achieve proper etiquette, correct movements with the techniques) 速、形の正の上に、理合いを弁え錬磨を重ね、運剣の速度を早くする事。
(With proper techniques and a good understanding of the theories of the techniques, movements will naturally become smooth and quick) 強、正と速の上に打突斬撃の効果を十分ならしめるため当たりの強みを錬磨する事。
(Building upon the correct, smooth and fast movements, the power of each technique will be brought out eventually) 威、正、速、強を身につけた上で尚、稽古を重ね、体を会得し、遅速・緩急・ 強弱を悟り、残心の要を知り、格調高い無限の品位と風格の境地を目指す。
(Once the above have been attained through diligent practice, your body will then fully immerse into the technique. With full control of speed and strength, along with the sense of Zanshin in response to the surrounding, your skill will then approach flawless perfection.)