Shove half a lemon and some herbs up it's bum. Put an absolute crapload of butter on it before you start cooking it, and baste at intervals.
Roast potatoes - parboil for 10 mins, drain and give them a shake, sprinkle on a teeny bit of flour or semolina, put them into really hot fat in their roasting pan and make sure they get coated in it, top of a hot oven, turn them over occasionally. Towards the end of the cooking time, throw some whole cloves of garlic, some woody herbs (e.g rosemary, thyme) and maybe a bit of orange peel, just to add a bit of extra flavour.
Veg - lean into cooking things in the oven. A couple of ideas: roughly chop up an onion, a red pepper, a couple of cloves of garlic and a few tomatoes, throw them in an oven dish with a little olive oil, a good pinch of salt, a small pinch of sugar, and a scant teaspoon of wine vinegar or cider vinegar. Chuck in some herbs (eg a sprig of thyme). Shove it in the oven and give it an occasional stir. Or, braise veg in the oven in stock e.g. chop carrots and celery into batons, put in an oven dish with vegetable stock to cover, again lob in some herbs, foil over the top, bung it in the oven.
Basically, herbs.