Welcome to the forum TonTon and to the world of oil painting. I started off with acrylics then changed to oils a year ago and I love working with oils now.
This is a good painting but I agree with David (Bushcraftonfire) that more contrast and a distinct light coming from one direction could improve it. A shadow from the vase would ground the vase and going from light to dark around the vase would give it a more 3 dimensional look. I have the same problem with most of my paintings and I try so hard to get the subject looking right that I forget about the lighting contrast. I too am working on it.
This is a good painting but I agree with David (Bushcraftonfire) that more contrast and a distinct light coming from one direction could improve it. A shadow from the vase would ground the vase and going from light to dark around the vase would give it a more 3 dimensional look. I have the same problem with most of my paintings and I try so hard to get the subject looking right that I forget about the lighting contrast. I too am working on it.