Been in a calorie deficit for over week now, but decided to give up weighing myself as the scales are beyond fickle. Instead, I've measured my waist, chest, arms, thighs and calves... bit more of a faff on but a much better indicator of progress.
Best way of doing it, for people that get down about not losing "weight", even though the actual volume of their body can be a lot less. Nearly every girl I know trusts the number on the scale more than their eyes or how they feel.
A load of people will just not get their head around that muscle weighs more than fat by about 20%.
The way I think of it is if you're in a calorie defect of 1kg per week, but you're doing doing any sort of strength training:
5 litres of muscle weighs the same as 6 litres of fat.
Your weight might not shift, but stick a pint glass against your belly, that volume has disappeared from somewhere.