People often express confusion about abstract art. Rather than thinking about it as being about a scene or a series of objects, or even a concept, think of it as being about the painter, painting and paint.
Because of this abstract art is very hard to make. Abstract artists are learning about themselves as painters, about paint, and about painting. There are no external references to check against - it's all new. Great abstract artists have established a consistent 'language' to describe their journey. Most have a solid grounding in colour and composition which they choose to manipulate in signature ways.
Abstract painters usually begin their works very freely, playing and moving paint around in an intuitive way, picking colours they like. In the flow stage they keep working until there is a natural 'stop'. Then the difficult part really starts; applying their knowledge of colour and design to finesse the painting. Most abstract artists overpaint a fair bit. They often stop between the flow and editing stage to 'get to know' their piece before finishing it. This process can take months.
Abstract art refers to art that is non-objective - or 'not about things'. Abstract painting ranges from the very graphic and to the very expressionistic. Some famous abstract artists you may be familiar with or can look up are Picasso, Willem DeKooning, Richard Diebenkorn, Joan Mitchell, Helen Frankenthauler, Joseph Albers, Piet Mondriaan and Mark Rothko.
Here are some of my abstract paintings. I experiment with repeating processes that work for me. Here you can see some of my 'strip paintings', and some of my 'backline paintings'. To learn more about these ways of starting abstract paintings, have a look at my Abstract Painting Ideas.