1 - Keep your hands dry
Hands are one of the most complicated parts of the body to protect from the cold, while still retaining freedom of movement. Once wet, hands quickly become cold. So you need to dry them thoroughly and keep them warm, using a small towel dedicated to this purpose. Even if it's inevitable that you'll have to take off your gloves at some point, to handle a fish or tie a knot, don't put wet hands back into gloves, and dry them thoroughly first.
To keep your hands dry, be careful not to get your rod butt or gloves wet, and if you do, dry them as much as possible before using them again.
2 - Drink and eat hot
Having a thermos of coffee for the morning and eating hot for lunch is one of the basics for warming up and prolonging cold tolerance. There are several ways to eat hot, such as a thermos, which keeps your meal warm for several hours, or a camping-type gas stove, which makes it easy to cook a meal, depending on your preference.
Although the stove takes up more space, it can be used on a boat or in a car, as it guarantees a hot meal at all times. The thermos, on the other hand, keeps you warm for around 3 to 4 hours.

3 - Using spinning sets
The position of your hand on a casting assembly brings you into contact with the reel's line, and therefore with the water it carries. This is particularly true if you're using braid that soaks up a lot of water. With a spinning set, you're not in contact with the line and your hand stays dry.
4 - Do not overheat the vehicle interior
When driving to and from the fishing area, don't turn the heating up to maximum, and don't wear all the layers of clothing. Sweating before getting out of the car and being exposed to the cold increases the feeling of cold.