Each day, find one thing that makes your feel gratitude for your partner.
You may find that you have thousands of things that your partner does, says, or is, for which you are grateful. Sometimes it might be hard to think of even one.
Do it anyway. Do it especially when it is hard.
Download a gratitude journal app onto your phone. Do this even if you have your own daily gratitude practices that you do elsewhere, in a journal or app. I use and love "My Gratitude Journal". There are some other ideas below.
Decide WHEN each day you will do this gratitude practice and create a reminder.