It's tough. No one needs a painter, yet everyone needs a painter.
One of the key things a painter needs to get started is knowledge. Not an academic knowledge, but the knowledge based on a real desire to be curious and wanting to find out everything. A good painter has to be willing to listen and learn from any situation, however trivial. Develop a habit of looking at everything that happens to you as a ‘material' to be used.
A good painter studies art passionately and thoroughly, and if you have never experienced the thrill of a great artist’s exhibition that grips you from beginning to end, then chances are you won't be able to produce one either. The inspiration is good, but so is the structure. Prepare a plan for a series of pictures, or an exhibition. It’s always good to get a feedback from an experienced and objective person on the merits of the idea before you spend a year painting it. So drafting a proposal is a good idea. Think of it as a business plan. You wouldn't start a business without a plan, so why a painting suit? You can always review it.
Knowledge, enthusiasm, inspiration and curiosity, plus an ability to spend endless time researching, comparing, experimenting, trying and hopefully, enjoying the process. There will be lots of ideas to pursue, but not enough time. Don't get sidetracked, because chances are you'll find an even better idea elsewhere, which will distract you from your primary objective. File it. Come back to it later and work on it then. No one knows it's there. It will keep.
Once you painted it, you need to sell it. Now that's the hard part. Make contacts. Make people aware of you and your painting. Expose. Join artists’ groups, exhibit where you can, promote your painting on the net. You will begin to hear what works and what doesn’t, and you will get some unexpected offers.
There is no evidence that a good quality painting will always be discovered, appreciated, published, and sold eventually. It is hard to get an agent, even harder to get a gallery to consider one seriously. So you do have to be very proactive and even if you only ever imagined you'd be a painter, you need to be flexible, - painting commercially, exhibiting with whoever invites, giving lessons, etc. A decade ago Lucien Freud looked down on a commission to paint the portrait of the Queen, but four decades ago the same man was painting lilies on the bathroom walls of dukes and duchesses.
You will also need to build a portfolio of paintings shown elsewhere, so when you do make a contact with a gallery of your dreams, they know you are a professional. If you impress them, they will help you. Eventually, you will learn to work faster and be friendlier to criticism. You will know ‘this will sell’.
As for now, all you can do is make sure of one thing. The day your painting finds the right wall, it is as good as it can only be.