Gratitude can be practiced like any skill. The brain notices what you train it to notice. Train it to notice problems and problems dominate. Train it to notice blessings and blessings become visible.
The practice is simple but requires consistency. Each day, notice something good. Write it down if that helps. Let your attention rest on what is working, not just what is not.
This is not denial of problems. Problems exist and deserve attention. But so do good things, and they often receive less attention than they deserve. Balance the accounting.
What three things could you be grateful for today?