I paint mostly in acrylics using Windsor and Newton professional or artist quality paints. I sometimes use mediums and retarders added to the paint as acrylics dry very fast and these are useful for extending the working time for blending etc. I occasionally try painting in oils but get very frustrated with the drying time and paintings cannot be varnished for months until they have fully dried.
I enjoy painting in acrylics because they can dry in minutes enabling me to build up many layers of a painting in a short time.
I have slightly different approaches to paintings depending on the subject matter. Sometimes I will try to paint fairly realistically usually using a photo reference. Other times I will just start painting and see where it takes me. (Often the case with my landscapes or seascapes).
I like to utilise the technique of glazing in many of my paintings which is painting in thin layers of semi transparent paint so that previoous layers show through. Many layers can then be gradually built up to give an element of realism in the painting.