Spreading risk in your account does not guarantee against a loss, but diversification is an important component to help you minimize equity drawdown and reduce systematic and single sided risk.
Always try to diversify the trade you are taking. Do not take more than one trade in the same direction (long/short) and in the same asset (symbol, underlying) at a time . Try to diversify your trades in various symbols (indices, commodities, currencies, shares).
When you receive multiple signals for the same underlying and direction do not copy blindly all the trades. Wait for more suitable signals that will diversify your global account exposure. This does not apply to signals in the same underlying but in an opposite direction to an already open trade. In this case you should take the countertrade to balance out your account.
When two assets are negatively correlated, they can be held together in a portfolio to reduce systematic risk and act as an natural hedge. Indices and gold are typically negatively correlated and are good complements to trade together.
Take a long US30 trade and complement it with a long gold trade but pass on a short gold trade the negative correlation between both pairs will act as a natural hedge and help you reduce your account global risk exposure.