How do I turn my YouTube channel into a business?

My channel has over 20 videos uploaded, and it has 15k subscribers. It has potential to grow at an average of 700 new subscribers per month.
There are two types of Youtube Channels, the First one which gets money from ads, and the Second one which gets money from affiliates and selling courses.
Having both types of channels was not so bad for me. However, the second type is very important for me. I started with a simple channel and quickly built a loyal following.

Creating a successful channel requires a lot of work and effort. To help you get started, I created a list of 12 critical steps that will help you grow your channel to at least 2X.

Design. Create an attractive design for your channels home page.

Optimization. For your existing videos, make optimization with VidIQ plugin.

Thumbnails. Creating super catchy thumbnails is about 80-90% of success. You can use this trick to make sure that your videos get more views than others.

Video lenght. Do 10 minutes+ videos. It will generate more income than less than 10 videos. It is a simple and effective way to promote new videos.

Subscribers. Watch your subscribers interact in comments and share your video. This will help boost your video's visibility and increase subscribers' loyalty.

Find some help. There's a big difference between having a video editor and having someone else help with developing and producing more videos.

Make A/B tests. A/B tests are a great way to get started. Follow the experts' advice and scale up your knowledge.

Follow these simple steps and you will be successful in YouTube.