The first EMA (50) must be positioned above the second EMA (100). When this has occurred, it is essential to wait until the price comes back to the EMAs. In turn, the Stochastic Oscillator is exploited to cross over the 20 level from below. The moment you observe the three items arranged in the proper way, opening a long (buy) order may be an option.
Ultimately, each swing trader devises a plan and strategy that gives them an edge over many trades. This involves looking for trade setups that tend to lead to predictable movements in the asset's price. This isn't easy, and no strategy or setup works every time. With a favorable risk/reward, winning every time isn't required. The more favorable the risk/reward of a trading strategy, the fewer times it needs to win in order to produce an overall profit over many trades.

Assess how much capital you're willing to risk on each trade. Many successful day traders risk less than 1% to 2% of their account per trade. If you have a $40,000 trading account and are willing to risk 0.5% of your capital on each trade, your maximum loss per trade is $200 (0.005 x $40,000). Set aside a surplus amount of funds you can trade with and you're prepared to lose. Remember, it may or may not happen.