The first thing to do is to not mix EMAs with MAs. Some people prefer to use EMAs and some prefer MAs, but for crossover analysis only use one kind. For instance, 20 MA crossing the 50 MA, or 20 EMA crossing the 110 EMA.
EMAs are more timely than MAs but are also more likely to get whipsawed. MAs are less timely so you'll get in the trade later than with EMAs but you are also less likely to get whipsawed and is thus a better signal.