When you have to correct a child, always use a sandwich.

Remember to catch children doing the right thing. Sincerely thank them, praise them and acknowledge them when they do the right thing and or things that you ask them to do.
Sometimes children do things you don’t want theme to do or are slow to do what you ask them to do. Sometimes children need to be corrected. Some people might call this confrontation or what I prefer to call carefrontation. Children, we all, need to know and have feedback when we need to correct course or make a change. Correction is always easier to take and almost always more effective when it comes from someone who we know likes us and appreciates us for positive things we do. When you do need to correct a child, or provide carefrontation, be sure to follow up, as soon as possible with sincere praise or appreciation. I like to call this a sandwich. Both sides of the correction or correction contain sincere praise and appreciation. You can even do this when there is a longer term grounding, i.e. no TV or phone for a period of time. All though the grounding, continue to acknowledge and openly appreciate the positive.
This does not mean that if a child is doing something that urgently needs correction (i.e. about to touch a hot stove) that you have to stick something positive in real quick. You don't, just make sure that they have been hearing the positive all along.