You want to start the creative practice you keep postponing

You keep postponing the thing you want to make. Notice what is actually happening, because it is rarely what we say it is. First, you are waiting for conditions — the time, the desk, the stretch with nothing else in it. Those conditions are not coming, and the waiting is doing something for you: it protects the work from being merely adequate, which is what all real work is at the start. Second, the first version is supposed to be bad. Not humbly bad — genuinely, unpleasantly bad. Every finished thing you admire had a first version its maker would not show you. Third, make the unit small enough that starting is not a decision. Twenty minutes, the same time, most days. Observe what happens in the twenty minutes rather than judging what it produced. What would you make this week if it were allowed to be bad?