What are the most common leaks for a losing/break even player?

[pepitannikita]

Do you play live or online? Limit or NL? What stakes? Knowing this, I would then ask you some additional questions in order to give you some specific information that might be more valuable to you.

Meanwhile, the number one, generic across-the-board answer is PLAYING TOO MANY HANDS by calling preflop and even being in the pot and then compounding that mistake by STAYING IN THE HAND TOO LONG by calling just to see one more card.