Check your main mirror and then your left door mirror to assess the speed and position of any other road users.
Signal left in plenty of time.
Make sure your car is correctly positioned to turn left, normally your road position does not change when turning left.
Reduce your speed, using the footbrake, before changing gear and before you start to steer.
Depending on your speed, select the appropriate gear, normally second gear, before steering.
Look at the road ahead and into the new road, look for any hazards such as parked cars, pedestrians about to cross the road etc.
After turning into the new road, check your mirrors, make sure your signal has cancelled and then build up your speed.