You cannot just produce art when inspiration strikes, you have to show up every day. And the first hour or two is simply a warm-up exercise until your muse finds you worthy of attention. It takes years if not decades of experimentation and practice to perfect your craft. You must be in it for the long haul. It’s important to schedule activities and avoid distractions, which can affect your creative productivity. You have to be organised and disciplined in order to be reckless and original in your artwork.

Do not be so busy reading books and attending workshops that you rarely have time to create. The best teacher is almost always experience and the faster you make mistakes, the sooner you will learn. Do not keep editing, revising and redoing work so it remains unfinished. Art is a process and nothing will be perfect. Each piece becomes not a destination but a stepping stone on your journey. While an amateur tends to change their style or medium as the mood strikes them, a professional artist knows that a “jack-of-all-trades is a master of none”. We are better off focusing our time and energy honing our skills than diluting our creative power (unsure if I agree).

Do not get too attached to your artwork because someday you will have to sell it in order to have the opportunity to create more art. Let it go, knowing it has taught you what you needed to know. Find out who your potential customers are & where. You need to build your reputation (market yourself) online and in the real world. Art is not a hobby or a pastime, it’s a business / career. We are not only creators, we are also consumers. Surround yourself with the work of others & do not isolate yourself from other artists because you feel envious of their success or unworthy of their attention. People will take your art about as seriously as you do.

Reference: http://skinnyartist.com/9-warning-signs-of-an-amateur-artist/