Your English is great.
Forgive that I probably don't speak your language at all.
There are a few things to look at. This photo is actually quite good. I particularly like the way the color works on her skin there. So you could use the original painting as a palette (picking color straight from the photo). And look carefully at where the color is cooler in the shadows, and where it is pinker, in her cheeks and so on.
So if you pick the corresponding colors and put them in your picture where they were on the photo, you should be in good shape.
And you may also want to pay attention to her hair line. The edge is soft at the top of her forehead and it is sharp where it hangs owing to that they are not connected in those places and thus the areas are more separate looking.
Like Hanzz said, there are tutorials for different things in the Tips & Tricks section.
"Not a bit is wasted and the best is yet to come. . ." -- remembered from a dream