Slumps would not exist if it were that easy to fix. Sometimes the more you think about something the worse things get. A stick of gum? OK if it works I guess.
Players have to understand, this is a new day. This is a new at bat.
Some times it could be a mechanical issue. If so fix it! IMO most slumps revolve around what's going on between the ears. Thinking about it, just keeps reminding you that you're in a slump.
I think it is good for young kids to understand the greatest hitters ever have gone through slumps.