Listed here are detriments to your bankroll. Even the best players can lose money, so, if you try to start off on the right foot, your chances of winning and not losing money are better. They are not listed in any particular order as all can cause the same result, loss of your hard earned cash.
1. Drinking or drug use. If you are impaired, can you really play the game as well as you think you are? Maybe sober up, then read this.
2. Being too tired. Gotta know when to quit playing. If you are too tired, your decisions wont be as sharp. And, when I see "asakjjkkkkkkkkkkkkkkkkkkkkkkkkkkkkk" come across the chat box, I know you have fallen asleep with your head on the keys.
3. Playing too many games at once. Yes, there are many that do it, and some that can do it well. But since poker is more about a "people game played with cards" than a "card game played with people", start with one game, get good at it, then move up.
4. Other distractions pull your attention from the game which prevent you from having all the information you need. I have kids running everywhere around my house. I generally don't start a game unless, its a freeroll or I know I will be uninterrupted (usually after they are in bed). Oh, if you think in a game you need no other information, you are a rookie and stick with the low games. Every hand is an opportunity to gather more information for you to make the best decision when it comes time to make it.
5. Bad internet connections. Why pay 10 dollars for a game use your poker odds knowledge to try to win and ignore the odds of your internet going out mid-game. If you pay 10 bux and the odds of the internet going out is 10% then the odds of you losing the game are....oh who really cares what it is...why not get a better connection and save yourself some money over the long run.