I am a huge advocate for the use of Expert Advisors. But like Pharoah pointed out, it is a beast that can easily betray you. For example, using the current candle to make trading decisions could exhaust your entire account in minutes or even seconds. Lesson learned: always use closed candles to make your trading triggers.
The biggest piece of advice I could give you is to DEMO trade your EA until you are 100.1% sure that it is working the way it's suppose to. DEMO trade until you're blue in the face, and then DEMO trade some more. And after you think you got it, DEMO trade for two more months.
MT4 has a tool called the strategy tester. It tests your EA based on historical prices. Honestly, I don't like it that much, but nonetheless it is another tool to guide you in the right direction.