Tip: before you set off, make sure your brakes and gears are working, and that your chain is well lubricated. Note also that in winter, the road is wet, so think of yourself and others by equipping yourself with full mudguards.
Tip: it's freezing in winter! Always remember to carry a small bottle of lock de-icer in your bag or coat pocket, so you don't start the day late or in a bad mood... (Very inexpensive, available from hardware or bike stores, and takes up very little space).