Most reputable sites allow you to download their software and start out on any number of games playing for free (and for this, you usually don't even need to register and/or provide personal information) or even for nothing more than pennies and small change.
Taking advantage of this opportunity is important for several reasons:
Once again, it can't be stressed enough how important it is to take advantage of this opportunity to play for free. Think of it as your own personal "training period" where you learn through trial and error and through practice. Also, don't forget, once you've started playing with and for real money, this doesn't preclude you from returning to the "no money" areas to bone up on certain skill areas and/or try out and learn new games.
Aside from the fun involved, playing for free is probably one the best aspects of online casinos vs. their land-based counterparts. There's really no excuse not to take full advantage of such an opportunity!
Continuing along this theme of 'no money play', it's also worth mentioning that many online casino offer free bonuses which also allow players to play 'for free' to a certain extent. On top of that, many online casinos - and several who have provided special deals to GamblingPlanet users - offer 'no deposit required' free bonuses (click here for a list of such offers) which not only give you the chance to play for free, but also to win REAL money. As with the opportunities mentioned above, any chance you have to hone your skills without dropping loads of cash should not only be pursued, but also considered a necessary part of your gambling development!