Mirrors and all round observation, looking ahead, scanning the road are all well and good practice, but how quickly you absorb and process the information is very important too.
To improve your processing of others around you use colours of vehicles to help you recognise them, - yellow car, white van, black lorry, red sports car and so on. Its much quicker than branding the vehicle.
Then its how they are driving - in control, not signaling, driving to fast, too slow, poor positioning, bad parking, blocking visibility, signaling directions, eye contact, flashing lights, hazard lights, reversing, swerving, pulling in, slowing down, harsh braking, overtaking.
Next are the other road users - cyclists - the professional, the wobbler, the slow rider, the racer, the teenager showing off, the child, the group of riders, the family, the not concentrating with their headphones on, the I can ride with no handlebars, the wheely kid.
Will I fit - this comes into play when sharing space, working around parked vehicles, overtaking cyclists, passing pulled in vans, busses and delivery lorries. Don't take risks, many wont hold back for learners so don't assume they will let you through, Instead become the cautious and courteous driver who assesses the situation before making the decision.
Who is behind you, who is beside you, what is coming towards you, what could be around the corner?
Pedestrians are unpredictable - elderly people have a tendency not to look before crossing, children and pets are unpredictable and very hazardous. Some pedestrians may be drunk or on drugs that affect their behaviour, balance and make them very hazardous. Joggers, runners, blind people, deaf or disabled all have their own risks. Those listening to music, those who just step out, those distracted and those who are in a rush. Assess their behaviour, talk about their behaviour. They are not just Pedestrians - they all behave in different ways and need you to be aware of them as a driver.
What colour are the traffic lights? Lights ahead - how far away are they? If they are green then they will probably turn red by the time you get there. Vice versa be prepared red lights will turn green probably by the time you get there, ease off the gas and prepare for the opposite.
Scan the road ahead to help you prepare.
You are expected to react and respond in the safest most proactive way possible to all situations you face, so planning ahead and assessing your surroundings is very important.