In freelancing, you must go with a single field. Make sure that you are learning all the pros and cons of that particular field if you want to be successful at it. It could be interior design and decoration [ออกแบบและตกแต่งภายใน which is the term in Thai] or any other thing that you are fond of.
YouTube is going to make you rich
You can also provide Promote youtube channel service [โปรโมท youtube, which is the term in Thai] or you can become an advertiser on Facebook. So, the point is that in freelancing you can do whatever you want to!
Be determined and focused
However, you will face a lot of problems if you are jumping into the pool without knowing the depth of it. The field might not be suitable for you. Thus, make sure that you are not impressed by the money; a certain field might be generating.
You should only focus on your own interests and make your first earning through it. Freelancing is a huge field where there are many sub-fields available that you must look to choose. Also, do not forget that you can be a winner despite the tough competition if you are willing to succeed.
Your will power is going to define the length of your career. It is said that slow and steady wins the race. So, even if you are slow to start with, you must remain steady. In the end, you will see that you will be right on the track.
Just make sure that you keep on learning the basics as well as the technical aspects of the niche that you have selected. Then, after some time you can improve your skillset. It is a whole journey that should never stop.