I agree with most of the others and would like to add a few basic rules that I was taught.
Your Risk/Equity Management Plan should be established before you begin trading and you should stick to it.
Your trade maximum risk should be established at 1% - 5% of your equity depending on your account(s) size and your risk tolerance. Likewise, your leverage should also fall within your maximum risk boundaries. You may trade below you max %, but never exceed it. Your trade size will dictate your lot size and leverage. If a standard lot is too big, lower it to a mini or micro lot. If leverage is too high, lower it. A risk/reward ratio of 1:2 is a good place to start for leverage.
Nietzsche said " a man without a plan is not a man". Of course women are also included. From what I've been taught, I would say a good Forex trader needs a plan with solid risk management that must be followed. The flexibility in the plan comes in the conditions to initiate a trade, but one must also maintain a consistent entry/exit strategy.
I am not trying to preach to the initiated, but I would expect that we have a lot of seekers here.