i always try not to be greedy but dont know whats is the problem in my mind i become greedy always.Recetly again i won 2-3 bets consecutively in directbet and i planned to withdraw that,but my greediness increased and started betting even more,and i got the result and lost all again. 
The way to do that is that before you begin a gambling session is to determine how much are you willing to lose and how much will satisfy you if you won and for how long you want play, do that and you will get better results.