Many artists however feel awkward about this. They have grown up believing that a painting is "of" something and should look like the original. This must be overcome to paint expressive abstract paintings.
I would be the first to say that I still have problems with putting thoughts into abstract paintings but I will most stronly claim that by painting abstracts I have improved as a painter immensely. I have a very loose almost semi-abstract style and enjoy painting with colour. You can see what I mean by browsing a few of the earlier posts on this blog. I do find that fellow artists do find some, if not all, of my work pleasing and likeable. Not sure what this means but looseness is something that many artists seek. It works for me, and I find this style so much easier since beginning abstract painting.
When I was asked by my art group to run a workshop on abstract painting, I developed a methodology to enable them to try it out for themselves. I have written about this on Squidoo and you can read and see a step-by-step tutorial here:-
I have also collated these articles together into one, free eBook available on Scribd for download.