1) If you have any leftover cooked vegetables don't throw them away - simply freeze in a bag and next time you are making cottage pie, shepherds pie etc, simply defrost, blitz in the food processor and add to your meat!
2) For perfect roast potatoes, firstly make sure the potatoes are of even sizes, par-boil for 7 minutes or until the edges are just softening, in a baking dish heat a couple of knobs of lard and 3 tbsp olive oil and a sprinkle of sea salt, drain the potatoes well and return to the heat to steam off excess water, then sprinkle with flour and carefully add to the hot fat, turning every 15 mins or so, should take about 40-50 minutes depending on your oven.
3) Make a list of everything that is in your freezer on your computer and use it when planning your weekly meals, saves both time and money
4) Don't throw away creme fraiche / butter tubs - wash and use as most tupperware. Though tescos tub isn't fond of the microwave. They are great for storing nibbles and the odd 1/2 pepper or even when measuring out small quantities.