If possible, play at a casino offering 3rd party audited returns. I always like the peace of mind of knowing that a casino that I am playing at is happy to have the likes of PWC review their returns. Don't be too fussed with the number though, as high historical return to player rates do not reflect a casinos inherent likely-hood of paying you more, but rather the fact that it has had, on balance, more astute gamblers playing there than at casinos with very low return to player rates. Casinos do not set their returns (on table and card games) - game mathematics and player skill dictate this.

Make sure the casino you play at has real 24/7 support. Almost all online casinos slap the 24/7 support claim on their websites but very few back it up with a real person on the end of a phone line at all times ready to take your call. If there is anything about a game offered by a casino that you are unsure about (rules, limits etc), then clarify this issue before you play...even if this means calling support for assistance before you start.

Take your time! One of the great aspects of playing online is the fact that you can think long and hard before acting. So really, there are no excuses for making rash gambling decisions, that may otherwise be brought about by the pressure of a full table of impatient gamblers.

Choose to play at a casino offering a nice juicy sign up bonus. Why play with your money when their are so many casinos giving away free chips?

Make sure you are in a place where you can concentrate. My favorite aspect of online gambling is that you can dictate the environment in which you want to play...quiet and peaceful, or amongst friends. Just make sure you choose which works best for you in terms of concentration before a real money playing session.

Play at a casino that is licensed. At least then you will have some recourse to the licensing regulators in the event of a serious problem.

When you find a casino satisfying the above criteria then stay with that casino rather than jumping around from one casino to the next. Establishing a relationship with a reputable casino will ensure that you are not cheated. Taking your chances with casinos that you do not really know and have no experience with can be dangerous.