What's the rule for roundabouts? Give way to traffic coming from your right that is already on the roundabout, unless road markings or signals tell you otherwise. Enter when there's a safe gap, keep to your lane, and signal left as you pass the exit before yours.
The basic routine
Use the mirrors-signal-position-speed-look routine on the approach: check your mirrors, signal if you're turning, get into the right lane in good time, slow to a speed where you can stop if needed, and look right for a gap. Giving way to the right is the core rule - you only go when traffic already on the roundabout allows it. Keep moving when it's safe, rather than stopping at a clear roundabout, but never force your way in.
Lane choice and signalling
As a general guide: to turn left (first exit), approach in the left lane, signal left, and stay left. To go straight ahead, approach in the left lane (unless signs or markings indicate otherwise) with no signal on entry, then signal left after you pass the exit before yours. To turn right or take a later exit, approach in the right lane, signal right, keep right around the roundabout, then switch to a left signal as you come up to your exit. Always follow any road markings and lane arrows, which override the general rule.
Types of roundabout
You'll meet several kinds. Mini roundabouts are painted circles where you still give way to the right but have little room to manoeuvre. Normal roundabouts have a raised island and one or more lanes. Multi-lane roundabouts need careful lane discipline and early signalling. Spiral roundabouts, which use lane markings to guide you outward to your exit, appear at some larger junctions. Coventry's ring road and its larger island junctions give plenty of chances to practise the busier types.
Common mistakes
The faults examiners see most are being in the wrong lane on approach, signalling too late (or not at all) when leaving, hesitating at a clear roundabout, and cutting across lanes. Most come down to reading the roundabout too late, which is why approach speed and early observation matter so much. Practising this on real Coventry roads with an instructor during driving lessons is the fastest way to build the judgement.

