1. don’t invest with money you need back in a hurry – transfer funds across when rates justify, and not to meet a deadlind, either abroad or at home.
2. sign up with a forex provider, to avoid using standard banks’ cut-throat rates and fees.
3. Pad all transfers by 10%, always leave 10% behind, to ensure you’re not stuck with last minute small emergency transfers for whatever reason.
Follow all of the above, and you should be able to stay on top of forex rates, or at least, not be damaged by them.