It's important to know beforehand how much money you're going to play. That is, if we want to play 200$ once those are spend (with or without earnings) we don't play anymore for that day. A lot of online casinos (like the ones linked at the end of this page) give you some free cash when you register a new account and we can use that money to play without losing anything. Anyway, the best way to win is to play small amounts in several casinos (or several accounts on the same casino); this way just winning a bet on one of them usually is enogh to compensate the other losts.
Another widely used variation of this rule is to set beforehand, not only the money we're going to play, but also how much of the earnings. For example, if in a bet we win $40 and we've set to play 50% of the earnings, we'll play $20 and the other $20 will be keept as non-playable earning.
This is one of the oldest and better know ways of playing on casinos. It's very simple, we bet $1 to the red color, if we lost, we bet $2 to blacks, if we lost we bet $4 to reds... at the end we will win and since the bet is incresing we usually compensate for the money losts.
A lot of onlines casinos give more odds (chances to win) to freshly created account (but be sure that they can't give lessodds that the normal ones because that would be illegal.) This way the new players is more easily "hooked" on the casino. Here the trick to use is easy to see: We create and account, play until we win some money, and then we create a new account. The amount of these initial easy earnings vary a lot from one casino to the other but is usually between $300 and $600.
We have selected this casino because they give up to $200 initial bonus and seems to give good earnings to new accounts. It also run as a local game with an exe file so it's more responsive than 100% web browser based casinos:
If you're good at poker this place is great because it allows you to play without money, so you can evaluate the site before betting money, and also they give you a $100 bonus, also as a local game: