There's no single answer to this.
Fish change behaviour throughout the seasons, they still need to eat to survive - the amount they eat varies and generally gets less the colder it gets.
They can also change location. Fish go where they feel safe, can eat or procreate.
So, it's a simple case of finding where they like to eat :w
You might find that simply changing bait will work for a while longer. The water is starting to turn clearer, you may have to change your approach to your swims, or even change swims altogether.
You haven't mentioned what type of water you are fishing and if you are targeting a particular species.
On a lake I used to fish, you could near enough guarantee blanking from October until March / April, it is quite shallow so just casting seemed to spook the fish. This changed though as the lake is match fished quite regularly through the colder months, so the fish are more used to noise and food going in.
On some venues, you can smash ice and catch with varying degrees of success.
Location is the first requirement of fishing, think in 3d - the fish may be at different depths.
Hard and fast rules made on one water, will be proven wrong somewhere else. Keep making small changes to what you are doing until you figure out what you need to do, follow the fish.
