Here is my take on a common trading strategy that uses the 50 and 200 moving averages to indicate a trend change.
In my version, I use two multi time frame EMA's. One runs at an input of 26 and the other runs at 104.
Typically these kind of crosses will involve a retest and sometimes may fail, but if the trend holds true in a reversal we can usually see pretty large gains.
As always, don't get over confident and always know your stop loss and take profit levels.