A Dictionary definition of a professional is ' a person characterized by or conforming to the technical or ethical standards of a profession; while amateur activities are defined as 'practising an art without mastery of its essentials.'
As a professional artist you must be able to consistently achieve a standard in your work for the gallery and for clients. How do you do this? What further skills differentiate the professional from the amateur? The successful from the Sunday dabbler?
There are three elements to consider.
Firstly, selection of subject matter.The professional understands all the elements that create a successful painting, the interplay of tone, form, colour, line, drama and beauty.
Secondly the professional thoroughly understands the capabilities and properties of their tools and materials.
Thirdly they have studied and attempted to master the processes by which those materials and tools can best be applied to the task.
Fourthly, ask yourself - am I 'seeing' or just looking?