Plan your route.
Look for bike paths, shortcuts, back roads and ways to avoid busy junctions, dual carriageways and step hills. You'll be amazed at how many ways there are from A to B!!
Don't be afraid to adapt your route at different times of the day. Also the best way into work, may not be the best way back home.
Get the right bike.
Speak to the experts first! For normal road or towpath commuting, you'll be much better off on a fast light hybrid, than a slow heavy and often complicated mountain bike. You'll be amazed at just how fast and how easily they roll and how quickly they will stop, when needed. Hybrids combine most of the speed of a road bike (racer) with the powerful brakes and easy to use gears of a mountain bike.
Get the right clothing.
That baggy jacket may cut a dash on the street, but get on your bike and it magically morphs into massive speed sapping parachute!! Cycle clothing, may seem a bit fitted at first, but you'll appreciate it once you're moving.
Reflective details will make you more visible to distracted motorists and longer arms and back will fit you as you ride.
Doesn't it rain a lot?
Though it certainly rains a lot in the UK, the weather is frontal, so it doesn't actually rain that often when you're riding. There's an often stated "fact" that if you ride five times a week, from 8:30 - 9:00am and home again 5:50 - 6:00pm for 48 weeks a year, you'll only get wet 14 days in the year.
Don't be afraid to drive on some days.
Why not drive a few days a week? Driving a few days a week, allows you to easily shuttle clean and dirty clothing between home to work and to avoid those days when the weather is bad.
Learn how to use the gears and brakes.
Modern bikes have gears that are so easy to use that you'd be crazy not to shift whenever the conditions change. When you're the engine, give it all the help you can!!
Cantilever brakes will stop you quickly in an emergency and allow you to smoothly control your speed.
Make yourself visible
Don't be afraid to light up your bike like a Christmas Tree!! Flashing LED lights are cheap to buy and run. Using calculator batteries they last for months and shine so brightly, that they are visible even in the day.
Reflective clothing also helps.