Make sure you only do business with reputable firms and understand how investor protection rules and compensation schemes will and will not protect you if the worst happens.
This website has several articles on opening foreign brokerage accounts, which I believe is a sensible step for some experienced investors. But you should always be careful and only make use of well-regulated firms. Never place your money with some dubious outfit that nobody has ever heard of based in a country that has no rules to protect investors.
And this isn’t just true when investing abroad – it applies at home as well. Only use companies that are fully regulated under your local securities law. And if someone cold-calls you try to sell you shares, put the phone down and report them to the regulator.