I recommend you look for those which are regulated and established in a decent jurisdiction. By decent I mean it is probably safer to trade with a regulated broker in the US than with a regulated broker in Somalia. Jurisdiction is no guarantee, but it will offer you safer choices
Try to start from a list of Forex Brokers accepting US traders as clients fx-list.com/brokers-for-us-traders You see, in this field the best way to find some reliable broker is looking for on some reliable platforms. I have been trading with a couple from the list for six months already and pretty satisfied with conditions and the income.