This method is for the person who has a good bit of coins, and wants to make a good amount of profit with minimal effort. Instead of making a bunch a small profit trades, or searching the IF market for a good deal, just pick one or two expensive players and trade only them. If you have a smart phone you can just you the smartphone app to trade, or whenever you are on the computer just use the web app. After I bought my new team, I was down to about 250k coins. I really don't feel like all out trading anymore, so this is the method I am currently using, mainly with Dani Alves and sometimes Thiago Silva also. In about a week I went from 250k to 420k doing only this, so that decent profit, especially with how little effort it required.
First off you need to keep track of the players value, which is very easy with only one or two players. You should use a player between a fifth and a half of your free coins. Because you're not really that concerned with your turnover rate, you can afford to list the cards slightly higher than normal and let them be relisted a few times, and just not trade until it sells. Now you're gonna want slightly different profit margins when using this technique. If I am trading someone who cost like 140k, then I want to make at least 3k profit. If I am trading someone around 50k maybe 2k profit. If I am trading someone around 20k then maybe 1.5k profit.
When you start you might want to try a few different cards to see what works. For example Thiago Silva's come onto the market listed at a buyable price about three times as often as a Dani Alves, but Alves sells for a buyable price probably twice as often as Silva. Find cards that actually sell often enough at a price you would be happy to buy at. The key to this process is that it is something you do throughout the day. Check the auctions every hour or so and then pay attention to when they end and just bid when they get there. Some hours you don't buy any cards and that's fine. This method isn't about constantly buying cards, it is about looking a good deal that will come once in a while.