I just completed a small painting (12" x 12") of a jar of pears and a pomegranate and it is hanging in the "Bin Gallery" at the Torpedo Factory for the month of July.
I can't emphasize enough the importance of practice to an artist. Musicians realize this, if they are professional. I remember when I was a child the sound of a neighbor who was a violinist in a nationally recognized orchestra practicing hour after hour. The student or wanna be artist who says "I just can't ..." or "I should..." is basically saying, "I don't have enough intention to be a professional." (This applies to me too, of course, and when I rest on my laurels and don't put in the time on practice, I see a decline. It may be slow, but it's the slippery slope!
Practice can include drawing, sketching, painting. You don't always have to get a product. Just moving the paint around, or trying a new color or medium, counts.
In The Way to Happiness, philosopher L. Ron Hubbard says:
"Learning bears fruit when it is applied. Wisdom, of course, can be pursued for its own sake: there is even a kind of beauty in it. But, truth told, one never really knows if he is wise or not until he sees the results of trying to apply it.
"Any activity, skill or profession, ditch-digging, law, engineering, cooking or whatever, no matter how well studied, collides at last with the acid test: can one DO it? And that doing requires practice." — LRH, Chapter 17-3, The Way to Happiness.