Give up on annuals, except one or two of your favourites. Stock up well on Mediterranean shrubs or tough herbaceous survivors such as catmint or bleeding heart.
Start practising water restrictions early on (only use a watering can) Plants suffer just as much from overwatering as under.
Plant lots of lily bulbs. They don't mind the hosepipe ban as they don't need watering and come up in July and August however dry it is.
Retire your small flower pots and planters. Nothing less than 2ft deep and 18" diameter will retain sufficient moisture. Use plastic pots rather than terracotta pots which absorb too much water. But if you hate the sight of plastic line your terracotta pots with plastic. (a carrier bag does the job brilliantly) Avoid metal ones as they get too hot and scorch the plants.
Never water fruit trees as they will develop a healthy thirst and become addicted to water.
Use Mulch or alternatively, compost and leaf mulch. Don't use grass clippings as these rot and the heat produced turns the soil sour.
Re-locate some plants so that the flowers don't dry out.
Enjoy the sun and be thankful that the weeds don't like the sun either!