A good starting point are the review sites, like brokerchooser, finder, motley fool, etc. Then find a couple of brokers that you find interesting and search their name + review in google. I've posted the same question on this forum and you could do a search to find more information, but most seem to go for IG, Interactive Brokers, T212, Freetrade, Finco Bank, Digero, etc. It all depends on what you are looking for, what your budget is, as well your initial capital size and frequency of trade. Are you looking to trade regular US shares or CFDs, spread betting. than examples as IG, eToro, CMC Markets come to mind