There is no reliable way to grow quickly. Usually it is a slow process, building an online community.
Using tools (like TubeBuddy) you can work on your SEO, to get your video searchable, and clickable. Your title and tags will help you be searchable. Your title and thumbnail will help you get more clicks on the vid. (there is a bit more to it, but that is a good beginning) Then, it is your content that will keep them watching, and hopefully, keep them coming back.
The content has to be something you are passionate about. If you are just trying crank out vids to get money, it usually shows through. To connect with your viewers you need to really have a love of your subject. The best content for me will likely not be the best content for you.
I see a guitar in your profile picture; are you learning? You can share your learning journey. Are you expert? Perhaps you can give tutorials. Find your passion.
Fast growth is relative to what your current subscriber number is, I have hit 5k in 2 years to me thats FAST growth. To others this might be slow.
Also fast growth causes self esteem issues, if your last video didn't hit 1000 views in 24 hours you feel you down and a failure. As others have said "slow growth" is better and easy to maintain at a level. Also if you have a fast growth which suddenly slows it might make you quit the platform.
If your doing Youtube to get rich or famous your not doing youtube for a reason that would make you successful. These things happen due to passion for your projects. Some of the most successful youtubers started just for fun and got lucky there channel became niche and made them successful.
This is kind of a dubbled edge blade.
Ive seen this happen many times.
Now, be minded, I dont have a solution to the "Grow fast" thing.
But I can, maybe, shed some light on what most People how Grow fast, wil experience.
Now, most People how Grow a large subscribe count in a very short period. They often made a trending video. They got Lucky, and I do mean Lucky, they hit the right tags, the right topic, the right trending, with One video.
And now they are stormed by New subscribers Who wants to see more.
There are two ways this could go. From this point on, You have to make the same type of video that attracted your New audience. But what do they want? The same? Forcing You to comply on a youtube niche You really dont care about. Worst of All, loosing those that first subbed You, for You. These subs are the ones You need to love most.
The number two event, You go back to making the old type of videos, the ones You like. Now You risk loosing All those that came for trending videos. Then You are dissapointing the newcomers.
Its not easy.
Im not saying this happens every time, but often, this is the case.
So take it slow on youtube. Set goals. And set a means on how to achieve those goals.
There are No easy way, no magic tag You can use. So build it up. Make a strong foundation first.