There are a lot of online casinos today. However, what you should first learn is how to minimize your losses. You want to make sure that you are actually winning money. However, for a beginner, winning might be a rare occasion.
You should first learn the games. In fact, make use of the bonus and free games to learn as much as you can from the games provided by the online casino. This way, you have an idea of what strategy you could actually have. You may also test the strategies to see which one works best.