Hello, Choose the one that have a licence and follow special rules of regulations. I recommend any form the list fx-list.com/brokers-for-us-traders as I have been using their services for a couple of months already and pretty satisfied with customer support and conditions for investments.
I wouldn't say concrete things. In my opinion, you should better search for them on topbrokers.com/forex-webinars There you can read about them and choose those you like. I can't see any obstacles here, this is costless.
It is not hard to find a good broker or even a broker to help you with trading. But I think it is not worth it to pay a person to help you with trading when you can do it by yourself. Firstly try to understand the basics of how the market works. Read some books about micro and macro economy. By reading these books you will understand how the market works and you will be able to understand what to invest in by yourself. Also it is very important to learn forex chart patterns. There are twenty eight patterns and an experienced trader knows all of them.