Nobody enjoys confrontation. There may be people for whom not addressing a problem is more uncomfortable than the confrontation itself, but no one looks forward to it. Despite this, it is something we of all ages must do on a regular basis, and make no mistake the child confronting a sibling and the employee confronting a boss are equally as difficult for the individual involved.
There are two important aspects to this topic: planning and defining.
Here is an example of a personal situation where I failed to plan. We have had very noisy, party happy neighbours for the past two years. On one night these neighbours were particularly loud and I ventured outside to confront them, sans planning. My request for them to keep the noise down was met with anything but understanding. While the confrontation was over in mere seconds, nothing was resolved.
Had I planned my argument I would not have chosen this particular time (2am); the venue (the street); the circumstances (a drunken party) or my frame of mind (sleep deprived). Admittedly, we cannot guarantee the perfect scenario but planning will at least reduce the possible negative outcomes. Had I planned my confrontation I would have chosen a more suitable afternoon time (not the morning as this group tend to rise later) and invited them to my home where I feel more confident and relaxed (and could practice my line of reasoning in the actual space). There is no assurance my request for quiet after midnight will be met, however, I will have been pro-active about a problem I have and would not have received a drunken retort.
If it went wrong the first time
Once a topic has been poorly confronted it is very difficult to revisit it later as the confrontee will have a bitter or trivial memory of the first attempt. A bitter recollection immediately places them on the defensive, while trivialising the event puts them in a position to dismiss the topic before your argument can be brought forward. This is not to say if the initial encounter went abjectly the whole topic should be discarded; rather state out right that your first attempt did not come across well and you’d like to revisit the matter.
Defining the problem in a way that fits with your values and practicing what you want to say can make all the difference in how successfully your confrontation goes and ultimately the likelihood of a favourable resolution.