While sparring is indeed an important element of Brazilian Jiu-Jitsu, drilling is often undervalued and neglected. By drilling technique, you develop muscle memory, speed, reaction times, and proficiency. All this leads to you being sharper, more fluid, and the technique becoming second nature to you. To illustrate this point, when you initially learn a new technique, you are not as proficient with it in the beginning making it more difficult to execute in live situations. However, after drilling these techniques you tend to be more confident and comfortable which increases your chances of success with it during sparring.
Take out a little extra time to drill. But remember it’s not “practice makes perfect” but rather “perfect practice makes perfect”.