When you are learning, you should never invest more than what you would consider funto lose. Dont add to your bankroll after losing everything youve invested. Wait until you are comfortable losing that amount again.
When you start winning on a regular basis, adjust your bankroll to maximize your earning potential. The general rule of thumb is you should be able to afford to lose 200 bets at the highest limit. So if the limit is $5 bets, then your bankroll should be $1000.
Track your wins and losses. This will help you figure out if you are winning or losing in the long run. Also, depending on where you live, you may have to pay taxes on your gambling income.