Can anyone please tell me how I can lose 1kg a week?

Well I currently weigh about 88kg and I would like to lose about 25kg in 6 months, so I would like to lose at least one kilo a week. So i would appreciate Any tips or idea you could give me to lose 1kg a week? Also how do I break out of the habit where I see I have lost like 4kg then think oh I can eat as much as I want again.. An then it all comes back on.:( so annoying.