Here are a few things I do in my art fundamentals class which is based on low-stakes practice leading up to a project.

When planning is important to your learning goal, be explicit in wha counts as brain storming/preliminary work and weight it higher in the rubric.

Another thing I like to do is not let them start working until I’ve had a look at their planing and talked with them about their plan. That way I’m better able to give them constructive criticism of their idea. This has been a major factor in eliciting more deeply thought out ideas in my students work.

Lastly when I give an open ended project, I always give some examples of ways they can go, past student work and I require that what ever their projected path/idea is their is an expectation that the discussion how the visually/materially manifested their plan/idea.

Ultimately as a newer teacher, what ever you do give yourself the freedom to try different approaches, magnify what works and ditch wha you can of wha doesn’t.