Most parents don't complain, and are more likely to leave the team if they are unhappy with how things are handled. So, it is good to have parents who will bother to give you feedback (even if it can be painful to hear).
Most of the time, this feedback is well-intentioned - and the parent simply wants an explanation for what has happened or wants to offer some suggestions about alternative ways to do things. Most of the time, this advice is well-intentioned (and the parent had no desire whatsoever to take over the team - or to try to order you around).
What parents want
Most parents have two objectives when they sign the child up: for the child to succeed and for the child to be happy. If you praise the child in front of the parent, you can rest assured that the child will give you a big grin - and you earn points in both columns. Do this as often as you can - and you will keep gripes to a minimum.
Any time that you start resenting the time that it takes to give this positive feedback, tell yourself that you could easily be spending double this time - and a lot less happily - talking to just one upset parent! In short, a good soccer coach makes the parents believe that they have wonderful, successful and happy offspring - which causes the parents to believe that the coach must be an absolutely brilliant judge of children.
Time to discuss problems
But, of course, you cannot please all of the people all of the time - and you may end up with a complainer or advice-giver despite your best efforts. If this happens, listen briefly to find out what the problem is, then schedule a time to talk about it. NEVER discuss any serious problem right before a drill session (or before a game). You have work to do, and don't need the distractions (and certainly don't need to be upset yourself if any harsh things are said).
Furthermore, if the parent is really upset, you don't want any confrontation to occur in front of your players or other parents. So, set the discussion for the end of drill practice - or schedule a time to call the parent later (if this is something where the child does not need to hear the conversation).
NEVER discuss any problems or complaints right after a game. If a parent comes to you with a complaint right after a game, make up any excuse that you can and get out of there. Usually, these complaints come after a hard game and a hard loss, when everyone is upset. Give everyone time to cool off - so that things are not said which are regretted later.
Soccer coaching communication skills
When you do talk to the parent, listen carefully to the parent's problem. Be calm. Try to get them to see things from your point of view. If at all possible, lavish some praise on the child during the meeting (remember parental objectives). Try to verify their reports that the child is unhappy (for instance, some parents want their child to be the goal-scoring star, while the child truly is happiest as a keeper or sweeper).
Volunteer to have a meeting with the parent and the child to talk about the situation. If the child truly is upset (for instance, he wants to be a forward, while you have rotated him to the back because he sorely needs to develop some defensive skills), talk about why you think that this is best. Usually you will be able to resolve complaints by open communication, and a calm approach to the problem.
Involve the club
However, some parents simply will not be satisfied, no matter what you do. This happens quite commonly with parents who were athletes, and ended up with non-athletic children, where it is easier to cast blame than to face reality about the child's lack of skill and talent. If it is clear that you are not getting anywhere, suggest that you set up a joint meeting with club officials to talk about the problem. In the meantime, call the club to give them a “heads-up” that they might hear from this parent, if it appears that the parent is truly irate.
If worse comes to worse, take heart that “parents-from-hell” tend to stick around for only a short time. Usually, you will find that they have been very unhappy with every coach whom their child has ever had - so they go back in the pool every season. In fact, don't be surprised if, when you call the club, you hear a large sigh come out of the phone - along with a comment of “Oh, no. Not them again.”