It is important to have a well-considered investment allocation strategy when trading in the forex market. Generally, it is recommended to allocate no more than 10-20% of your total investment portfolio to forex trading. This ensures that you diversify your investments sufficiently, while still giving yourself the opportunity to benefit from the potential of forex trading. In terms of which currencies to trade in, it is important to consider which countries have the most stable economies and which currencies have the most liquidity. It is also important to factor in your risk appetite when making decisions about which currencies to invest in.