Well, for one thing, it is winter and until the light starts getting longer and stronger, flowering will be minimum to none.
If they are several years old, they are probably pot-bound and the roots need trimming and the plant repotted. Get a good potting soil like Miracle Grow or Scotts that has vermiculite, perlite, peat, and time-release nutrients.
Geraniums are light feeders, but if indoors need more feeding that if sitting outside. When was the last time you fed?
Your plants also might need trimming. You can actually root cuttings, so don't just throw the cuttings away.
Why aren't my geraniums flowering? to feed or not to feed? they are several years old...?
Geraniums are light feeders - don't overdo.
Perhaps they have gotten leggy and could use a good trimming.
See source for basic geranium information.
Reply:geraniums only bloom on new growth. Give them a good trimming. The new growth should bloom.