Growing your own food: The Basics
Any open green space, hard area, fence or wall can be used to grow food - there’s an edible crop for almost any growing conditions.
See Designs for more on what to grow where
Most veg do prefer plenty of sun, so pick a sunny plot if possible, though some will flourish in partial shade, berry bushes for example.
Veg for partial shade http://organicgardening.about.com/od/vegetablesherbs/a/shadeveggies.htm
Shelter and structures
Hedges, walls and buildings create microclimates (some useful, some best avoided), and can be used for climbing plants.
Vegetable garden microclimates http://www.harvesttotable.com/2012/02/vegetable-garden-microclimates/
A gentle south-facing slope is best, but anything apart from a steep north-facing one should do (though salad and some herbs will grow even here). You can use ridges (long, low mounds of soil, ideally running north/south) to maximise the sun-facing areas. If you have a steep slope you might want to create terraces to make access easier.
Growing on a slope http://www.ehow.co.uk/how_8100365_grow-vegetables-slope.html
You'll need plenty - either mains water from a tap (this is ok in Leeds unless there is a 'hosepipe ban', in which case try using 'grey water' from baths, washing or washing up etc), or some way to capture and store rainwater on site, such as a butt fed from a shed roof perhaps - otherwise you'll have to bring lots with you in containers. A watering system (or just bottles feeding the roots) makes life much easier, especially in raised beds and containers which tend to dry out. Furrows or mounds along a slope will help to retain moisture, and a pond will encourage frogs and toads (which eat slugs).
Bottle wattering systems; Google lists lots of options
Rainwater harvesting http://www.growveg.com/growblogpost.aspx?id=243
In general, the better the soil, the better the crop, though fruit and herbs tend to be less fussy. Leeds mainly has heavy soils, which benefit from the addition of organic matter such as 'blood fish and bone' (and perhaps biochar) - and remember that previously uncultivated land may be low in nutrients. Ideally you'd find at least a spade's depth without too many stones or debris, and good drainage. If the soil is shallow, you could import some soil or compost, use raised beds or containers (possibly using up-cycled materials) - or just grow perennials, fruit bushes or trees.
DIY soil testing http://organicgardening.about.com/od/soil/a/easysoiltests.htm
See Soil health and safety for additional important information, and sources of soil and compost on the Map (on the Resources layer).
Buildings / storage
You might want a shed or lockable store for tools (these won't be allowed in parks), or if you're not growing at home maybe you could borrow some access to a nearby building? How far away is your plot? If you're walking or using public transport will you realistically get there often enough? If you drive, is there somewhere convenient to park?
Security (vandalism, ownership, pests)
Are you happy for passers-by to share your crop? If not, can you make your site secure? (You won't be allowed to fence off plots in public parks). Would it help to demark your plot in some way, maybe with a low hedge so people at least know it's private. What about foxes, cats and vermin? Do you want to keep them out, and if so will you be keeping out hedgehogs who would help by eating slugs?
The amount of work required will depend on whether you go for a traditional approach, one of the low-maintenance permaculture-type approaches, or just plant perennials and bushes. Do you plan to work alone, or in a small group such as your family? Or with a larger group (maybe involving an existing community, or one you build up yourself)? Do you even hope to make this a commercial venture?
See People and Processes section - especially Finding a Workforce
Allotments are not free, and you'll have to pay for seeds, plants, tools etc. But you can make compost and plant food yourself, swap seeds and plants, and share tools with others if you join or form a group. Feed Leeds is hoping to encourage Tool Banks, Seed Banks and a network of local mentors and champions to make it easier for people to get started, but it is early days for this.
Allotment rents http://www.leeds.gov.uk/leisure/Pages/Allotments.aspx
Please advise of any broken links, or links you think should be included here