Goal setting is an effective way to make a good profit playing Hold'em, but most people's goals focus on profit instead of how they play.
With the erratic swings involved in any Hold'em game, there's no possible way to set realistic goals based on profit when it's out of your control. Before you know it, you're in the hole and trying to make your losses back too quickly.
You should instead make consistent playing, day in day out, your main goal. How you play is the only thing you can control in the game of poker. The outcome is totally out of your control, so stop spinning your wheels worrying about luck and how much money you want to win. Focus instead on playing consistently and you'll net more profit in the long run.
Consistency is the major difference between a winning and losing player. Anyone can play good cards, but the problem for most people comes when they're getting cold cards or going through a string of bad luck. You have to focus on playing your best poker every hand to make it through those times and come out a winner on the other side.
There are many amateur players out there who play like pros, but lack consistency. They'll make great sums of money when the cards fall their way, but when they catch a cold run they tilt their bankroll away. It's very easy to do this, especially when playing online, because cyber chips are so easy to blow. You never have to physically commit your chips to the pot which makes it easier to go all-in on anything.
To become a consistent player you must treat poker like a business. Good business sense dictates that you use the money you have wisely to reap the best profit in the end. In poker that means always having enough in your bankroll for the game you're in. You won't have to worry about the day-to-day fluctuations and the bad beats won't bother you as much, so you'll be calm and play consistently.
Although poker is a gamble, the fluctuations can be weighed in your favor by consistently playing better than your opponents.