It is possible to be grateful for what you do not have, in order to manifest it.
When you get stuff, you become grateful after the fact. You usually reserve all of your gratitude for receiving. This is the ego's version of receiving God's blessing and appreciating it.
So you'll notice, you are only ever grateful when you have received something. Which means, having something is tied to gratitude, and not having it is not tied to gratitude. And therefore, a lack of gratitude will lead to LOSS, because you're choosing to not appreciate its presence, not see it, not experience it.
You can't appreciate what 'is not'. And when you do not appreciate, you enter poverty because you're not seeing (appreciating) that you have stuff.
So, what happens when you deliberately, pro-actively become grateful for what you do not have yet? Gratitude and having must go hand-in hand, so if you are grateful and you don't have, the 'having' MUST manifest to correspond. Your mind projects it.
I tried this some years ago actually and had some minor success with it. Of course I was fighting the ego and my own unconscious mind which is far more powerful, but it did work to a degree.
Proactive gratitude manifests the very thing you are grateful for. Fear and worry is the opposite, which deprives you and leads to lack.
This is loosely similar to the law of attraction which says you should feel what it would feel like to have it already, in order to draw it to you. Well, really what's going on there is you're *appreciating* and being grateful for the experience of it, as though it were real, even if you don't have it yet. And then the universe, as a mirror, reflects back to you what you're broadcasting. You're saying "I already have gratitude for this" and the universes says, ok, you already have this and you're grateful for it. Ding. It appears.
Just throwing this out there in case anyone wants to give it a try. There's nothing wrong with playing with this while you're here, just know that having by itself without the gratitude leads to greed and control, which is the typical downfall of the 'law of attraction' approach.
Those who are grateful cannot be greedy because they appreciate their abundance. Greed comes from AND leads to scarcity. Eventually therefore a hoarding use of the law of attraction bites itself in the butt because too much ego-getting stands in the way of appreciation which disables the attractive power. Gratitude is the way to go.