They key to losing weight is not to do anything drastic like stop eating, partake in any "fad" diet or exercise till you drop.
The best way is to set a target weight loss (say 1 stone) and aim to lose a pound per week - so 14 weeks for the whole plan.
Weight gain and loss is simply the result of calories in and calories burned so make sure you burn more calories than you take in. Roughly speaking 3500 calories equates to one pound in weigh which makes for an easy 500 calories per day.
For me I have calculated that I need 2500 calories per day to maintain weight so I limit to 2000. For each day I calculate the net loss/gain and record it as a - or a plus (so yesterday for example was a -5 - meaning that I have lost 500 calories). At the end of the week the addition should come to -35 or more.
I also make sure my fat total does not exceed the daily allowance.
If I exercise (which I try to do 3 times per week) I can either eat/drink more or lose weight faster!
For me it has worked as 8 weeks in I've already lost a stone. Best of all I haven't had to make any radical lifestyle changes - just take care not to eat too much.
Hope this helps.