Hi Wook. I've been away and just got to seeing your first oil painting. The picture has wonderful colors and a great composition however I know the quality of your drawings and I can understand you would not be overjoyed with the results of this oil. You are capable of so much more.
Here are some things I've noticed. I believe you are working with very dry pasty paint. The lines and globs in the white show that. If you add some oil or Alkyd medium it will flow better and you will have better control of what you can do with it. The thickness you are using is what one would normally use for Impasto painting. Also the blending is much better if you have your paint slightly thinner. When deciding what to add to the paint keep in mind that oil will prolong the drying time and Alkyd medium will quicken the drying time. Also just use a tiny bit at a time when mixing because it's very easy to wind up with a washed out color if you use too much.
The most important question is did you enjoy painting it, and will you be doing more oil paintings?
Thank you from the most inner depths of my heart, that is the post I was looking forward to read. As always, I am very happy to see you.
As a matter of fact, I wasn't even planing to do the painting at all, I had idea of taking the photo of paint on canvas as background for my website (under construction) so, I had to so something, I took peace of sheet, (don't even know what sort of sheet it was

) and tried oil colors I bought while ago. As I am self educated artist, I didn't knew that I will need something to dissolve the colors, but later on I figured that out and I used a bit of olive oil (yes, for food one

). Today I paid a visit to bigger shops and I didn't found any professional tools (brushes, oil colors nor canvases), only school ones, so I didn't got my self anything. I will search few online stores in my country and see what they have.
I have plan to do more experiments with the oil colors, but when I get some free time.
In meantime, I do need to see some tutorials.

Thank you very much, I really appreciate your guide.