Well, it's really no different than trading a stock, in a practical sense. You can trade it exactly as you would a stock. If we're talking about stock-index ETFs, the advantage is that you can trade a specific industry or sector - or entire market - without having to buy each individual stock.
If we're talking about commodity ETFs, though, I don't know about those. I've traded the Gold and Oil ETFs, but they tend to lag the things they're tracking. For example, if Gold is up 2%, then GLD (the ETF) might be only up 1.9%. If Gold is DOWN 2%, on the other hand, GLD will be down 2.1%. So, I don't like them for long-term trades. short-term, maybe.
(on the other hand, you can see the advantage in shorting it)
If we're talking about commodity ETFs, though, I don't know about those. I've traded the Gold and Oil ETFs, but they tend to lag the things they're tracking. For example, if Gold is up 2%, then GLD (the ETF) might be only up 1.9%. If Gold is DOWN 2%, on the other hand, GLD will be down 2.1%. So, I don't like them for long-term trades. short-term, maybe.
(on the other hand, you can see the advantage in shorting it)