Oil painting is very satisfying, you can muck in it, change it, wipe it off, let it dry and paint again or even when it is just set.
Saying a painting is "set" means that the paint doesn't slip and you can add more paint and move forward.
Often an oil painting is done in tree stages: the block in; the colours, shapes and details, then the finishing touches.
The block in is shapes and background colours. But even before that is the drawing and composition that is really the most fun. Creating your design and placing all the parts. Creating side to side, top to bottom and back to front.
Everything works in threes: background, middle ground and for ground. And each of these has the tree previous areas to work in.
Colour and details can be painstaking, but exciting. Here is where you spend a lot of time, creating details in all the shapes not forgetting the threes: background, midground and foreground.
Some colours suit the background better than elsewhere but don't forget the background has three levels as well : background, midground and foreground.
Also the detail is less in the background, less but still important.
Now is when you create light and dark or at least bring it forward to the second stage.
All grounds can be worked on at the same time, once you've had some practise.
