Those are the words of Michelangelo, renowned sculptor, painter, and architect, at age 87. Despite his enormous skill, he recognized that there was still more to learn. Like any craft, learning how to paint requires commitment, time, energy, and desire.
Following his example, I continue to read and take workshops to improve my craft. Recently, a friend gave me Clear Seeing Place by Brian Rutenberg, which details his experience and process as a painter in both South Carolina and New York City. I highly recommend it to fellow artists. In addition, he also posts studio visit videos which are wonderful to listen to while painting.
Besides reading and practicing, I find that, as a visual learner, taking workshops from other artists is also helpful. Search out artists whose style you admire and see if they teach workshops. Recently, I have taken from Dawn Whitelaw, Thomas Kitts, and Jennifer McChristian. Workshops allow me to pick up helpful nuggets I can incorporate in my process plus travel and meet like-minded artists along the way.