De-Clutching too early. A vehicle has two functions. You either stop or you go. There are parts in the middle but ultimately you do either of these two things. It therefore makes sense that by pressing the clutch too early you disengage the drive and can no longer move when needed. What you need to achieve is earlier planning and observations so you avoid pressing the clutch too early.
Using the brake against the clutch. This is some what related to the above. The vehicle is driven with the gas and clutch. If you are trying to move at a junction you should apply the gas and the clutch together. Find the right balance and make progress. It comes down to the planning part of the drive.
Over signaling. Yes, its in there. A theme is running because if you actually look and plan well ahead its easier to remove a lot of indicators from your driving. I'm referring to positioning early to pass park vehicles, not signaling to return to the left or pass a bus. Just remember an indicator can be just as confusing as not signaling at all.
Rolling changing. I often take on new students coming to me from other instructors and one of the biggest problems is the rolling change. What does this mean? Basically there are two main reasons you need to stop the vehicle. At stop junctions. Traffic lights and perhaps you could argue when there is an obstacles in front of you. All other times the vehicle should be moving albeit very slowly which may appear as though its stopped. Get the rolling change right and you will make more progress and save fuel and just enjoy the drive more.
Roundabouts. Possibly one of the harder junctions to master as they require can change very often and rapidly. The biggest problem I find is that clients are looking too often to stop rather than looking for gaps to go. If you master the points above the process of going becomes much easier.
Taking your time. I actually don't want you to rush. I often see students trying to stop and move at the same time which often results in the vehicle stalling. Use the time, arrive at the right moments and plan to move away safely. If it takes 10seconds longer its better to move safely they risk going quickly.
Possibly the most common error I see is not staying left. Its one of the first rules of driving. Try to stay left unless over-taking passing parked vehicles or turning right.
Roundabouts, but this time a term we call straight lining. Its where someone enters the roundabout but rather than holding their lane they move into the inside rather than the outside.