When modelling in clay, avoid smearing the clay about, or automatically, arbitrarily, smoothing out all the tool marks, etc. Smearing produces an unintended, uncontrolled form (and combined with smoothing, usually a lumpy and uninteresting surface). Instead I want to add or remove clay in response to an observation or an intention.
As in drawing, so in modelling and in painting, each mark, each piece of clay, each brushstroke, ought to be part of an act of seeing, of paying attention to the subject and the work.
So practise, practise … so that the medium becomes a familiar tool to enable that act of seeing, not a hindrance to it. As familiar as this pencil or the hand that holds it.
And another thing: don’t hunt for something ‘meaningful’ or ‘significant’ to paint. It isn’t really about the content, or even the form; the significance is in the paying attention.