I've set writing goals for myself from the first novel I wrote several years ago. Word count daily/weekly goals seem to work best for me. When I'm in the swing of things, my typical goal is 1K (1000) words a day, with an average of 5K/week.
For the most part, these are reasonable and attainable goals for me, given the other commitments in my life. What I've learned over the past few years is to adjust the goals based on circumstances. For example, my monthly goal for July was 10K total. (And I reached it.)
It doesn't help to motivate me if I've set the goal too high. Rather than work harder to make the higher goal, I give up. If, on the other hand, I set realistic goals, sometimes I can exceed them.
Some days or weeks are more stress-filled than others and I have set a time-related goal instead. Write 1 hour per day, for example, regardless of word count. That kind of goal gets me though when the words are playing hard to get.
Today, I hit my 1K goal. I just don't think the partial scene I wrote is working. But that's OK. Something on the page means something I can work with. I think what I have written is the equivalent of 'throat clearing' as the story shifts gears a little. It will probably all end up on the metaphorical cutting room floor. The take home message for me is just write. It doesn't have to be perfect, it just needs to be on the page.
"Heal Thyself" is at nearly 51K. The next several scenes will be quite dramatic and I am looking forward to writing them.