The most important factors to consider when choosing a broker are simple and basic. Maintaining the security of your funds should, without a doubt, be your priority. To begin, ensure that the broker you pick will not defraud you of your funds. Only use a broker who is based in and regulated by a financial authority in a renowned financial center to ensure your safety. Second, be sure you'll be able to get your money back if the broker operates ethically but goes bankrupt for any reason.
One approach is to only deposit with brokers who have deposit protection provided by their regulators (such as regulated brokers in the U.K. or Australia, for example).
If your broker goes bankrupt, the government will bail you out by repaying your funds up to a certain amount, although this could take some time. Aside from that, seek for a broker with a solid financial standing and a positive reputation.
Following these procedures, you can evaluate what your possible brokers have to offer in terms of asset range, spreads and commissions, overnight financing fees, and transaction execution speed and reliability, and make an informed decision.