This feeling is a tough obstacle in any language and I think the only way to grow past it is to practice new vocabulary and creativity in your writing/speech. For example, you could word your story as:
Cut my bangs! (always spelled as bangs, and you can drop the "hair" because it is a hairstyle. Similar to how a "ponytail" wouldn't be a "hair ponytail")
1. I cut my bangs. It's been a long time since I haven't had bangs.
2. I've wanted to try new bangs and I've thought about it many times before I finally decided to cut it by myself.
3. I don't have any hair-cutting scissors* so I just cut my hair using normal scissors.
*scissors are always plural, you can think of it as two blades (each a scissor) joined together to create a pair of scissors. "Scissor" as a singular form is basically never used except for terms such as a "scissor kick".
4. My bangs don't look like what I expected, but I like how they came out.
5. I forgot to bring the hair iron from my mom's house so it's hard to make them look good. Instead of buying a new iron, I ended up buying a hair roller because it was cheap.
6. However, the hair roller I bought was bigger than I expected which means I'll need to get one in a different size.
***
I split up the story into independent ideas to loosely visualize how my take on it went. I think the difficult part in the story is number five and I actually have the same issue with Korean and I think it would help if I showed you how I would write it.
나는 머리 아이언이 엄마집에 잃어벌려서요. 그래서 잘 보기 좋게 만들지가 어려워요. 그래서 머리 아이언을 사야 되는 생각있었어요. 그런데 머리 아이언보다 머리 롤어가 더 싸니까 머리 롤어 샀다.
LOL I haven't practiced Korean in so long so I apologize if it is ugly to look at. I repeat a lot of stuff because it is what I am comfortable with (그래서 and 그런데 are very easy to use :P ). As I practice my Korean, I will start to have a better understanding with how/when to use words and the common ways to structure sentences. I feel like the solution to avoiding repeating the same words and sounding robotic/unnatural is to practice using the words/sentences that we are uncomfortable with and to receive the criticism that will guide us in the right direction.
I am positive that you are able to reword my Korean to sound a lot more natural and also in 5% of the time it took me to write it up. In the same way you can use your knowledge/experience with the Korean language to reword my sentence, you will be able to reword your same sentence in English to sound a lot smoother without repeating the same words. All it takes is a little practice!
