The Laws of the Game (Laws) are maintained by the International Football [soccer] Association Board (IFAB).  The same Laws apply in every match, at every level world-wide.  While the Laws are standard across the world, modifications and interpretations are allowed, particularly for youth games.  The Laws are relatively simple, there are only 17, and rely on the interpretation of the Referee within the “spirit of the game”.  The Laws are intended to provide that matches should be played with as little interference as possible, and in this view it is the duty of referees to penalize only deliberate breaches of the Laws and that impact play.  Constant whistling for trifling and doubtful breaches produces bad feeling and loss of temper on the part of the players and spoils the pleasure of spectators.

Hand Ball

The foul is called Deliberate Handling.  Considerations, all in the opinion of the Referee, include: A) was it deliberate, B) did the players hand hit the ball (foul) or did the ball hit the hand, C) did the player try to avoid it, D) player's distance from where it was kicked, E) did the player make themselves bigger, stretching their arms out, raising their hands, etc.

Offside Calls 

Offside, not offsides. One tends to watch a player kick the ball, then look to see if the player receiving it is offside.  The player must be in the offside position when the ball is touched or played by his/her teammate, not after. 
A)  If it is played by an opponent, there is no offside. 
B)  If it is played by his/her teammate and deflects off an opponent but was never possessed or controlled by that opponent, it is offside.
C)  If the offside player is offside and comes onside to retrieve the ball after it is touched or played by his teammate, it is still an OFFSIDE offense as he/she was OFFSIDE when the ball was last touched by his/her teammate.

A player would be in an offside position if they are in their attacking half of the field (for 10U it would only be from the Build-Out Line on the attacking half) and closer to the goal than the second to last defender (two defenders one of whom may be the goal keeper) and closer to the goal than the ball.

Out of Play (Out of Bounds) 

The ball is out of bounds when it wholly crosses a boundary line.  Even if a ¼” of the ball has not passed the plane, (wholly over the outside edge of the line), on the ground or in the air, the ball is still in play.  The ball is out of bounds on the person it touches last, not the last person to kick it.  The throw in goes to the opposing team.

If fully across the goal line and not a goal, a goal kick (last touched by an attacker) or corner kick (last touched by a defender) is awarded.

Illegal Throw-Ins 

Throw-ins must be performed properly whether they go in play or not.  If the throw in is performed properly but does NOT go in play, then it is a retake.  If the throw-in is not performed properly, whether or not it goes in play, the throw-in goes to the opponent.  You do not get a free ride just because it never went in.  The ball is in play when it breaks the outside plane of the line.

HOWEVER, for the younger age Divisions (8U and 10U) at the beginning of the season, allow for a second chance by the same player if first throw-in is not fully correct.  If the second throw-in is still not technically correct but does not impact the resultant play, let it go but remind the player of what he/she needs to correct.

Goalkeeper Handling & Playing 

A keeper can come out of his/her penalty area, just not with the ball in his/her hands.  Goalkeepers are also a player on the field.  They can go anywhere on the field they want.  Deliberate Handling or a “Hand Ball” would only be called on a Goalkeeper when the goalkeeper touches the ball when it wholly over his/her own Penalty Area line.  It is the ball, not the goalkeeper that determines handling.  On punts, as long as a goalkeeper releases the ball before it is wholly over the line, they can exit the penalty area to kick the ball.  Even if the ball may have been slightly over the line, and it looks like it may still have been in the goalkeeper’s hands, it is considered trifling.  Now, if the goalkeeper is completely over the penalty area line (like both feet) with the ball in their hands, that is deliberate handling, and is a Direct Free Kick (DFK) for the opponent, with the ball placed just outside the Penalty Area, not breaking the plane of the line.  Leniency is to be afforded younger players.

Goal Kicks and Free Kicks do not have to leave the Penalty Area to be in play 

The ball is in play on Goal Kicks and Free Kicks in the Penalty Area when it is kicked and moves, it does not have to leave the Penalty Area to be in play (2019 law change).  A free kick includes both Indirect Free Kicks (IFKs) and Direct Free Kicks (DFKs).  The defending team should leave the Penalty Area before the kick is taken.  However, if the attacking team decides to take a quick kick before all opponents have left the Penalty Area, they are allowed to do so.  In this case, if an opponent is already in the Penalty Area before the ball is in play, and that opponent plays that ball in any way, the goal kick or free kick is retaken. 

Passback to the Goalkeeper 

It is an infraction resulting in an Indirect Free Kick (IFK) when a teammate passes the ball back to their goalkeeper, generally with their feet, and the goalkeeper handles the ball (picks it up with their hands).  It has to be a Deliberate Passback to be called.  A deflection off a teammate or kick that unintentionally goes to the keeper is not a violation of the passback law.  If the goalkeeper attempts to clear the ball (kick it into play) but fails, the goalkeeper can then handle the ball (cannot be a "deliberate" fail).