One thing I’ve found that makes photographs more interesting is using a surface reflection of your subject. It could be trees reflecting in a lake, or still life like the photos below.
The fruit was photographed on a glass coffee table, and the nuts were on a granite kitchen counter. All you need a smooth surface and at least some light coming from behind you or to the sides to “front light” your subject.
Also notice that the fruit photo has a darker background because the only light was a lamp in the room to my left side. The nuts had bright window light behind me, as well as reflected window light off the fridge and kitchen cabinets in the background.
This particular type of photo benefits from a wide aperture setting. A blurred background gives it more impact by making the subject stand out. The apple and orange were shot with a 28mm f/2.8 at f/3.2, and the nuts were done using a 50mm f/1.8 at f/1.8.
I used prime lenses, so my flexibility in distancing myself from the subject was limited, but with a zoom lens, you can experiment with backing away and zooming in on the subject to see how it affects your depth of field, in addition to aperture settings. Usually, as you get physically closer to the subject, the depth of field gets more shallow, like these pictures where I was just a few inches away.
Hopefully this will give you some inspiration for rainy day, indoor photography!