New to all this?
Every game sorted by what your garden actually has.
See the gamesA mini pitch doesn't need a rectangle of lawn to work.
Tape, line-marking spray or a rope mark a boundary and a halfway line to fit whatever shape the garden has. Goals go at least two big steps from windows and flowerbeds, and the whole layout can go down and come back up again for the next session.
I spent ages trying to picture a proper pitch shape onto a garden that is really an L around next door's shed, before realising the pitch was supposed to fit the garden, not the other way round.

Work with what you've got
Setting up a football pitch in the garden starts with an honest look at the space you've actually got, not the one you're picturing. Shape is what actually catches people out: an irregular layout, a shed in one corner, a flowerbed cutting into one side, is the normal starting point, not an exception to plan around.
Three decisions, in order
Garden goal placement and boundary lines come down to three decisions, taken in this order. A rough 5m by 3m clear patch is enough to work with; anything roomier is a bonus, not a requirement.
Mark the boundary first, in whatever shape fits. Tape, line-marking spray or a rope laid along the ground outlines the playable area around any shed, tree or flowerbed already there, rather than forcing a rectangle.
Goals go at least two big steps from anything breakable. Windows, greenhouses, delicate flowerbeds and the car all want that clearance, and aiming the goal so shots travel away from the house rather than toward it cuts the risk further than distance alone. Cones or a taped goal-mouth work as well as a bought goal.
A halfway line is optional, but useful once there's more than one game. A second taped or chalked line splits the space for two-goal games, running across the widest straight stretch rather than trying to bisect an L-shaped plot evenly, and disappears again for games that don't need it.

Built to last more than one weekend
A layout that survives more than one weekend comes down to what it's marked with. Line-marking spray sold for grass is designed to last through several sessions of ordinary weather rather than washing off after one shower, so it suits a boundary worth keeping for a while. Tape works for a quick one-off session on any surface, including grass, though in our experience it does not grip a lawn the way it grips paving. A boundary marked on grass is more likely to need re-laying before the next go than one on a hard surface, where it can also be left down longer. Left down for weeks on paving, it's worth checking after a damp spell, since it can leave a residue. A rope or set of cones can be lifted and stored in under a minute, for a layout that needs to disappear completely between sessions.
Something to play on it
Once the boundary and goals are down, the boundary game turns keeping the ball inside the garden fence into the challenge, and the corner target-shooting game uses any natural corner the layout creates.
Quick answers
Painter's tape for a single session on any surface, including grass, line-marking spray on lawn if the boundary needs to last, or a length of rope laid along the ground all work. Tape and rope lift away in a minute; line-marking spray is designed to last through several sessions before it fades.
At least two big steps of clearance from windows, greenhouses, delicate flowerbeds and the car, aiming the goal so shots travel away from the glass rather than toward it. Cones or a taped goal-mouth work better than anything fixed.
No. The boundary can follow whatever shape the garden actually has, working around a shed, a tree or a flowerbed rather than needing a clear rectangle.
Keep going
Three places to go next, now the pitch itself is sorted. If you are still deciding how big the goals should be, what size football goal to put in a garden sets it out by age. Before you mark the pitch, check the garden for hazards first.
Every game sorted by what your garden actually has.
See the gamesA turning game built for exactly the tight, awkward layout you've just marked out.
See the turning gameA garden penalty shootout that works on the same layout.
See the shootout gameTonight's five minutes
It comes up again just as fast for next time.