If you google 'setting writing goals' you'll find lots and lots of advice, most from more successful writers than me. I can only share what works for me.
When I first started, I received a lot of advice on setting goals involving word counts. One thousand words a day, five thousand words a week, thirty thousand per month, two books per year, lots of numbers. And I try to make those numbers though that's not how I set my goals day by day or writing session by writing session.
I set goals by scenes or chapters. Sometimes they might be 10K or 1K. By finishing a scene, I feel like I've moved the story forward no matter how large or small the word count. Then I usually walk away, do chores, sleep on it, do some shopping, all the while thinking on that next scene. When I sit at the keyboard again, I'm ready to dive into the next scene. There are occasions when I already have that next scene ready in my mind. Those are days when the numbers really add up.
Some people have a certain amount of time to write and their goal is to spend that time wisely. I'm not sure how that works out.
But if you're not meeting the goals you set for yourself, perhaps you need to look at different styles of goal setting. Not making your word count? Try setting scene goals.
Do you set goals by words count? By time? By chapter or scene? What works for you?