It does have its challenges though, but with a bit of sensible prior planning and the right mental attitude it's the best time to be on the water!

Keep Warm - make sure you are paddling in suitable gear, prepare to fall in and stay warm. You can add a outer shell, be it a fancy cag or something as simple as an old waterproof to keep the wind and extremities at bay. Add layers as necessary, but definitely do not wear Cotton as it will make you colder as it retains the water when wet.

Move your feet regularly - Icy feet are a horrible feeling and can make or break your enjoyment. Wriggle your toes, walk along the board and get to your knees regularly to keep the blood flowing.

Wear something on your head - A huge amount of heat is lost through your head so stick something on pre, during and after your paddle. Have a pair of gloves on, or to hand as well.

Study the forecasts -Things can change quickly in the winter months, paddle within your limits and be prepared to change plans as necessary. 

Let some one know where you are going - let them know when you expect to be off the water, and then let them know when you are off. 

Set up your changing ritual in advance - get changed on a mat to keep temperature, have clothes ready to be put on in order and easily accessible