Firstly if you are BF then you need to give yourself a break and concentrate on baby, now is perhaps not the best time.
Other than that my absolute best tip is to read the 5:2 threads. It is the best diet I have ever found, very easy and very healthy. 10kg off is a great target, but most of us find once you start to fast you can keep going without any hardship.
Ok I had baby no 2 two weeks ago. Put on hardly any weight despite eating terribly. Am same weight as I was when he was conceived. Alas that is 110kg so way overweight. Though I could obv do with losing 4 stone what I really want to do is lose 10kg. I think I looked good and felt healthier when I was that weight which was in about 2005.
So, any encouragement helpful. Would like to do it by Easter. Planning to cutdown bread and stop chocolate and cake etc and walk lots.