Think before you plant: New garden? Before you rip everything out, establish what you'd like your outdoor space to achieve, says Anna Pavord

New gardeners, proud owners of the very first patch of soil they can call their own, generally think of plants before anything else. The act of putting a plant in the soil is a kind of christening. It's an act of faith too, a sign that they hope to be around in the same place long enough to see the plant flourish and grow. But actually, plants should come a long way down the list of priorities for the novice gardener. The first and most important question to think about as you gaze at your patch is: what is this garden for?

If you start writing down responses to that question, you find you have acquired a ragbag of ingredients that may have an important bearing on the design of the plot. If there are small children in tow, you need a flat, soft area where they can fall off swings and climbing frames and a lawn where they can stagger around with their trucks and footballs. There's no point in having an outdoor space if your children, especially small ones, can't share it. That may mean putting a sandpit where you actually dreamed of having a cutting patch, a non-stop succession of dahlias and delphiniums, asters and roses to pick for the house. If you stay with gardening, that time will come, but it may not be yet.

If you decide to hang out washing rather than drying it in the bowels of an expensive machine, you will need a line and a dry path to get to and from it. Pegging washing on a line is one of the quickest ways to save an enormous amount on electricity bills and at the same time feel good about your carbon footprint. Lines aren't beautiful, but the retractable ones that coil themselves up in a dial no more than 17cm across are practically invisible when you are not using them and can be rigged up anywhere.

Some novice gardeners may not want to do much actual gardening at all, but conversely, do not want to look out every day over a scene of threadbare grass and rotting fence. Their ideal garden will look good and demand little attention. Our eldest daughter comes into this category. Lawn, terrace and box bushes in galvanised pots are the extent of her present gardening ambitions, but that's perhaps wise, as she's got five young children. Topiary is an instant pick-me-up, particularly in an urban garden like hers, where a lollipop bay tree, dressed with lights, does as much to cheer the scene as any mixed border could ever do.

She's a dedicated sun-worshipper too, and if that's a priority, you need to mark out the part of the garden where the sun lingers longest. Privacy is an important consideration too, particularly in town gardens. A first-time garden is usually small and certainly the typical one I am imagining is no more than 40ft by 20ft and surrounded on all sides by other houses. Privacy is a ticklish business where close neighbours are concerned. To throw up an impenetrable Berlin Wall between you and them could be tactless. Trellis is a useful compromise and you can always pretend it was forced on you by the speed of growth of your climbing rose.

Aesthetes among the novices will by now be thoroughly irritable and complaining that gardens should have as much to do with the soul as with the necessity of a washing line. So they should, and when the list of necessities is securely written down, you can ask the second question: "How do I want this garden to feel?"

This question produces as varied a response as the first. Some urban gardeners, as short of space inside as they are out, want their gardens to be extensions of their homes, with a great deal of hard paving, good furniture and lighting. The garden for them should feel like an extra sitting room, gnat-ridden perhaps, damp occasionally, but an important overflow of living space. Closet countrysiders may want to pretend their patch is actually a corner of some Sussex meadow and picture it swagged with honeysuckle and waving with ox-eye daisies and scabious. This is a difficult trick to bring off with suburban trains hurtling by on one side and lorries grinding through their gears on the other. A leafy retreat is an excellent goal for a small town garden, but it is best made acknowledging the urban setting, using "un-wild" plants such as bamboo, acanthus, fig, vine, alchemilla, euphorbia, wisteria.

While you are working through this process, take note of the features in the garden that you would like to keep. On a new estate, there may be nothing. In an old garden, there may be a fruit tree, or a good bulwark of evergreen laurel or box that, tidied up, could lend an air of venerability to the new garden that will emerge around it. If you do not know what a tree or shrub is, give it a year's grace to show you what it can do before you turn it over to the axeman.

The mood of the garden will dictate its eventual style. It may be clipped classical, random cottage, modern hi-tech, or some intensely personal vision of Byzantium, that no one has ever imagined before, but which exists in your head and wants to get out. Do not let anybody, particularly gardening writers, tread on your dreams. The patch is yours and needs only to please you.

All this thinking and doodling will have done nothing physically to change the view outside the window, but it is a vital part of the gardening process. Before you can create, you have to know what it is you are creating. Don't think of the job ahead as a makeover to be finished in the shortest time possible. A garden is a work in progress, and the longer you stick with it, the more engrossing it becomes. Next thing you know, you'll be opening it for the National Gardens Scheme.