A chunk of the job is repetition - phraseology, doing things similarly repeatedly, etc. If you’re not studying on your off-time, start. If you’re not practicing phraseology with a few classmates you trust and are doing well, start. Especially if you have the book open and can call each other out with the examples right there.
The more you do it, the less frantic it feels coming out. We use a ton of phraseology very little in ATC, and you can tell when those things aren’t as frequently used.
You’re coming in from not using these words to using them a lot, so the more it can be spit out correctly, the better. If that means you take five extra seconds to process it before you key up the mic, then take that time to get it right the first time.
Also “correction” is your best friend as long as you don’t unkey. 😉