Dropped ball

When you have a dropped ball, the ball is only in play after it is dropped and hits the ground. In other words, a player cannot kick the ball that has not hit the ground. Similarly, you cannot just hand the ball over to the GK. The GK, when they are the player to receive a dropped ball, is most likely going to pick up the ball anyway. But it does not mean you can just hand it over to them and call it a dropped ball.

Positioning around the penalty area

When a defender commits a direct free kick foul around their penalty area, we must know if it happened inside or outside. If it was inside, the restart will be a PK. If it was outside, then the restart will be a FK. The difference is immense. 

Oftentimes, when the inside or outside decision is in relation to the top of the penalty area (the line parallel to the goal line), then the lead AR may be able to help the referee (of course, the AR may be too busy with an imminent offside decision). But if the question is about one of the vertical penalty area lines, the decision is 100% on the referee.

So if you suspect that there may be a challenge by a vertical penalty area line, adjust your positioning. Otherwise your inside/outside decision may not be correct.