Initial energy on Extensive earth works to shape the land to be receptive to water absorption,is to be recommended.

Make terraces when farming on slopes
use living and any other type of barriers on steep slopes to collect and contain any organic material that is about and mobile

In Permaculture the rule is to harvest water to the point of Zero runoff.
This means that all of the rain that falls on an area is absorbed by the terrain and not a drop leaves it.

By building dams,ponds or Swales, with inter connecting ditches,

Bio swales to absorb water
http://answers.yahoo.com/question/index;...

If there are enough of these ;the places ,where before ,the rain water ran over the ground into the rivers and on to the sea ,in a matter of hours or days.

It now runs into absorbent dams or Swales and saturates the ground and eventually reaches subterranean water deposits ,taking many months to do so.

Or it fills up ponds that can be used for Aquaculture.

And so a convex situation that repels water is transformed in a concave ,absorbent one and turning the area in to a sponge.

The more it looks like the moon the better,many holes and if they do not hold the water but leak ,the water is not lost it is in the ground for months

In Spain and Portugal , many examples of ancient Moorish Water harvesting be found ,such as Aqueducts and tanks underneath the patios ,which collect the rain water from the roofs ,.

NOTE
The roof water of a building can run via a ditch ,trough the chicken house ,cleaning it and end up fertilizing the vegetable plot
(this is called the creation of energy flow).

WATER CONSERVATION

IN THE HOUSE one can connect the sink straight to the toilet cistern and so use the water twice ,first to have a shave and then to flush the toilet
also if you bend the ball valve you can regulate the level of the cistern

Always have your Grey water and Black water systems separate,so that the sink and shower water goes directly into the garden saving on irrigation and at the same time ,making the sewage smaller and easier to deal with ,

This also goes and irrigates the garden but via a cistern of two compartments and a French drain ,on which you plant trees,

And cars can be washed with rain water ,it does not have to be drinking water.

ON THE LAND ,

Only use small tractors for initial shaping and earth works
then preferably no till methods
Heavy machinery compacts the soil and will raise salt content to the surface do not have too many Cows
which will do the same

Compacted soil does not absorb much water.

Economic systems of irrigation, like drip irrigation
and water harvesting design,

Use a lot of stone walls ,that condense water in the night
and plant leafy plants ,for the same purpose,

Build wind breaks ,to counter act the drying effects of the wind and farm towards Aggro forestal ,using as many trees as possible to limit evaporation

Using shade nets before we have tree cover

Have some tall scattered shading trees at intervals to break the suns rays.

MULCH & SOIL CONSERVATION

Cut down the weeds before they produce seeds and leave them where they fall.
They will cover the ground add organic matter on top,(you can use saw dust,leaves green or dry),

Plant big leafed plant around the plots to use for mulch

The humidity is preserved underneath and promotes the development of worms(there exists no better compost than their excrements)and a variety of micro biotic life which together within the mulch produce more topsoil.

The mulch also keeps the ground temperature even and guards against the impact of the rain ,which would other wise brings salt to the surface if on unprotected land.

Mulch also prevents the soil from drying out because of the sun and,wind erosion.

Try to minimize disturbing the top soil so that organic structures remain intact and continue working ,building soil.

Plant DIVERSE,in guilds and companion planting to spread the chemical requirements and releases to preserve soil balance,
Do not use chemical fertilizers use compost.
References :
http://byderule.multiply.com/
some more relevant answers in this page under water
http://byderule.multiply.com/journal/item/5

When you water, you don’t vae to water indiscriminately, use a watering can and water at the roots.

Lastly, plant items that are native to your conditions. Discuss this with your local nursery.

Best of luck.
References :